Orange County
High Occupancy Vehicle ( HOV)
Operations Policy Study
ORANGE COUNTY TRANSPORTATION AUTHORITY
Prepared by:
Parsons Brinckerhoff Quade and Douglas, Inc.
August 1, 2002
Orange County 1 August 1, 2002
HOV Lane Operations Study
1.0 Introduction
1.1 Brief Background
High Occupancy Vehicle ( HOV) lanes have been an innovative and integral element of
the national surface transportation system since the first lanes were introduced as
demonstration projects in New Jersey and Virginia in 19691. In California, the first HOV
lanes were provided as a toll bypass on the San Francisco- Oakland Bay Bridge
beginning in April 19702. Since that time, the HOV system in this state has expanded to
include over 964 lane miles located in most every urbanized county3.
While HOV facilities in the state encapsulate a variety of differing design and
operational characteristics, more than 90% of the projects in California are concurrent-flow
lanes, separated either by a buffer area or striped without any separation from the
adjacent lanes. HOV facilities in the state include freeway- to- freeway interchange
direct connector ramps, direct local access ramps, freeway ramp meter bypass lanes,
and toll plaza bypass lanes. All but toll plaza bypass lanes are found in Orange
County. In fact, Orange County has provided more freeway- to- freeway HOV connector
ramps and direct access ramps as part of its HOV lane system than any other HOV
system in the U. S.
Within the state, HOV lane eligibility rules vary from a restriction of two or more persons
per vehicle ( 2+) to a 3+ minimum occupancy requirement. All but one project in the
four- county Los Angeles basin operate full- time ( 24 hours, 7- day/ week). The one
exception is State Route ( SR) 14 which is being tested as a part- time demonstration.
Part- time concurrent- flow operation ( weekday peak periods only) is found throughout
the Bay Area, Sacramento and on one project in San Diego. In the San Francisco Bay
Area, part- time operations open to general- purpose traffic have been designed to look
like typical freeway lanes, and thus do not have any difference in how they are striped
from adjacent lanes. Projects operating in southern California on a full- time basis
restrict access to designated openings in a buffer- separated area. The nature of
operation and the access design are issues that go hand- in- hand, with one influencing
the other.
These variations in HOV facility design and operation have led to periodic debate over
the most appropriate statewide or local policy. For Southern California specifically, this
debate led to the passage of several legislative bills influencing HOV design and
operation. These Southern California HOV bills include:
t Senate Bill ( SB) 699 on September 11, 1987 resulting in Caltrans practice of
adding a four- foot buffer separation area to concurrent- flow HOV lanes,
specifically the county’s first HOV lane project on SR- 55 within 18 months of the
Bill’s approval.
1 Fuhs and Obenberger, HOV Facility Development: A Review of National Trends, 2001.
2 Caltrans Division of Traffic Operations, High Occupancy Vehicle ( HOV) Guidelines for
Planning, Design, and Operations, July 1991.
3 Legislative Analyst Office, Effects of Part- Time Operation: HOV Lanes on Route 14, April 2002.
Orange County 2 August 1, 2002
HOV Lane Operations Study
t SB 63 on July 26, 1999 lowering the minimum occupancy on the El Monte ( I- 10)
HOV lanes from 3+ to 2+.
t Assembly Bill ( AB) 769 on June 29, 2000 rescinding the prior legislation and
raising the minimum occupancy requirement on the El Monte ( I- 10) HOV lanes
back to 3+ during peak commute hours due to overcrowding on the lanes.
t AB 1871 on September 8, 2000 temporarily changing the hours of operation for
the HOV lanes on SR- 14 in Los Angeles County. This legislatively mandated
change from full- time to part- time was intended to serve as a demonstration of
the effect of changing HOV hours of operations in this corridor. In April 2002
the Legislative Analyst Office ( LAO) examined traffic patterns in the corridor and
concluded that the “ conversion to part- time operation had essentially no effect
on traffic congestion.” 4 Despite the sunset of AB 1871 in June 2002, Caltrans
continues to operate the SR- 14 HOV lane part- time as a demonstration of part-time
HOV operations with buffer separation and limited access.
The Orange County Transportation Authority ( OCTA) is responsible for planning,
funding and in most cases administering construction of HOV facilities in Orange
County. The California Department of Transportation ( Caltrans) is responsible for
construction and operation of the HOV lanes. The California Highway Patrol ( CHP) is
responsible for HOV lane enforcement. To date, OCTA has developed over 200 lane-miles
of HOV facilities, one of the largest systems found anywhere. Currently, OCTA is
administering the construction of HOV direct connector ramps at the I- 405/ SR- 55
interchange. An additional 26.8 lane miles of HOV projects are currently programmed
by OCTA, including the completion of HOV lanes in the SR- 22 corridor.
1.2 Purpose of This Report
At the meeting of the OCTA Board in June 2002, Chairman Todd Spitzer addressed the
issue of Orange County HOV lane operational policies. Chairman Spitzer stated that
“ Orange County and the state have 15 years experience operating High Occupancy
Vehicle ( HOV) lanes. There have been many emerging issues nationwide about how
those lanes are best operated, and I think Orange County Transportation Authority
( OCTA) should continue its leadership role by examining current practices in Southern
California.” Chairman Spitzer cited three specific issues related to HOV lane operations
policy. These issues include:
t Full time ( 24- hour) HOV lane operations versus part- time HOV lane operations.
t Limited HOV lane ingress and egress points versus unlimited HOV lane access.
t Other significant HOV lane operational policies currently under discussion.
This report responds to the specific issues raised by Chairman Spitzer. It provides an
overview of the Orange County HOV system and explores whether the current
countywide operational policies continue to support the goal of providing for safe and
4 Legislative Analyst Office, Effects of Part- Time Operation: HOV Lanes on Route 14, April 2002.
Orange County 3 August 1, 2002
HOV Lane Operations Study
efficient operation. Past California and national experience is reviewed through
available studies and reports.
Within the short time period assigned by OCTA to research and prepare this report, it
was necessary to reference available data and reports to provide the basis for
developing pros and cons for different approaches to HOV operation and design. Data
and reports included publications by Caltrans, the California Legislative Analyst Office
and other national sources. Supplemental information was provided by OCTA and
through interviews with various responsible agency staff. In some cases the available
data was either incomplete or inconclusive. The investigation team applied their
collective experience and differing perspectives in trying to provide as concise and
comprehensive a response as possible to the various policies in question. As with any
policy discussion, technical, institutional and political input is applied. This report
attempts to present technical and institutional information pertinent to making or
sustaining sound public policy.
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2.0 Overview of Orange County HOV System
2.1 Extent of the Orange County HOV System
The first HOV lanes in Orange County were opened on SR- 55 in November 19855.
Since that time, the HOV system in Orange County has evolved to encompass five
freeway corridors and 200.5 lane- miles. HOV lanes are currently provided on the I- 5, I-
405, SR- 55, SR- 57 and SR- 91 freeways in Orange County. Table 2.1 lists the existing
Orange County HOV lane segments and the respective date of opening. Figure 2.1
depicts the growth of the Orange County HOV system since inception. Figure 2.2
offers a comparative graph of growth in HOV lane- miles nationwide.
Table 2.1 - Existing HOV Lanes
Route Limits Lane Miles Date Opened
I- 5/ SR- 1 Separation to South Avery Pkwy. 12.2 July 1996
South of Avery Pkwy. to El Toro Rd. 13.4 October 1997
El Toro Rd. to South of Alton Pkwy. 11 July 1996
South of Alton Pkwy. To Newport Ave. UC 14 October 1992
Newport Ave. UC to Santa Ana River 9.8 May 1996
Santa Ana River to South of Broadway St. OC 9.2 September 2000
I- 5
South of Broadway St. OC to Beach Blvd. 9.8 January 2002
Subtotal 79.4
I- 5/ I- 405 Separation to North of Irvine Center Dr. 2.6 July 1996
I- 5 to SR- 73 17.6 May 1991
SR- 73 to I- 405/ I- 605 Separation to Atherton St. UC 27.4 January 1989
I- 405
SR- 73 to I- 405/ I- 605 Separation to Atherton St. UC 1 February 1998
Subtotal 48.6
SR- 55 I- 405 to South of SR- 91/ SR- 55 Separation 22.6 November 1985
Subtotal 22.6
SR- 57 I- 5/ Sr- 22/ Sr- 57 IC to Lambert Rd. Off- Ramp 19.8 June 1992
Lambert Rd. to Los Angeles County Line 3.6 August 1997
Subtotal 23.4
Los Angeles County Line to Staton Ave. UC 5.6 June 1999
Stanton Ave. UC to East of Gilbert St. UC 5.3 December 2000
East of Gilbert St. UC to East of SR- 91/ SR57 10.6 February 2000
SR- 91
East of SR- 91/ SR- 57 Sep. to Riverdale Ave. OC 5 August 1995
Subtotal 26.5
Total 200.5
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
5 Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
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Figure 2.1 – Total HOV Lane Miles in Orange County
0
50
100
150
200
Total Lane Miles
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Year
Figure 2.2 – Total HOV Lane Miles in the United States
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
2,200
2,400
2,600
Total Lane Miles
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
Year
Orange County 6 August 1, 2002
HOV Lane Operations Study
Additional HOV lanes or project extensions in Orange County are currently
programmed for I- 5, I- 605 and SR- 22, and are planned for SR- 73, SR- 133, SR- 241 and
SR- 261. Figure 2.3 illustrates the extents of the existing HOV system in Orange
County.
Figure 2.3 – HOV Lanes in Orange County
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
Orange County 7 August 1, 2002
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HOV direct connector ramps have been completed at six separate interchange
locations, while HOV direct access ramps are currently provided at seven locations
along the I- 5 Freeway corridor in Orange County. These freeway- to- freeway direct
connector ramps and direct access ramps represent the most extensive number to be
implemented anywhere in the U. S., and have created an HOV lane system that allows
carpoolers and transit users to get from one end of the county to the other without
having to leave the HOV lanes. Additional HOV direct connector ramps are currently
under construction at the I- 405/ SR- 55 interchange located immediately to the north of
John Wayne International Airport. Table 2.2 lists the existing HOV direct connector
ramp and direct access ramp locations in Orange County, along with the
corresponding facility opening date. Additional HOV direct connector ramps and direct
access ramps are currently planned for Orange County. Figure 2.4 illustrates the
existing and proposed HOV direct connector and direct access ramp locations in
Orange County.
Table 2.2 - Existing HOV Direct Connectors & Direct Access Ramps
Route Location Facility
Type Date Opened
NB Off to NB I- 405 & SB On from SB I- 405 Connectors July 1996
NB On From Barranca Pkwy. & SB Off to Barranca Pkwy Ramps October 1992
NB On from NB SR- 55 & SB off to SB SR- 55 Connectors March 1996
NB Off to Grand Ave. & SB On from Grand Ave. Ramps March 1996
NB On from Main St. & SB Off to Main St. Ramps May 1996
NB Off to NB Sr- 57 & SB On from SB Sr- 57 Connectors May 1996
SB On from Gene Autry Way & NB Off from Gene Autry Way Ramps September 2000
NB Off to Disney Way Ramps September 2000
SB Off to Disneyland Drive Ramps September 2000
SB On from EB SR- 91 & NB Off to WB SR- 91 Connectors January 2002
I- 5
NB On From WB SR- 91 & SB Off to EB SR- 91 Connectors January 2002
SR- 91 EB Off to NB SR- 57 & WB On from SB SR- 57 Connectors February 2000
I- 405 NB Off to NB SR- 55 & SB Off to NB SR- 55 Connectors Under Construction
NB On from SB SR- 55 & SB Off to NB SR- 55 Connectors Under Construction
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
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Figure 2.4 – HOV Direct Connector Ramp and Direct Access Ramp
Locations in Orange County
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
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2.2 Statutory Requirements
Title 23 of The United States Code, Section 102 establishes the authority for the United
States Department of Transportation ( USDOT) to approve HOV facilities. 23 U. S. C. 102
states “ the Federal Highway Administrator may approve on any Federal- aid system
projects which facilitate the use of high- occupancy vehicles and public mass
transportation systems so as to increase the traffic capacity of the Federal- aid system
for the movement of persons.” 23 U. S. C. 102( a)( 1) provides for State Highway
Departments to “ establish the occupancy requirements of vehicles operating in high
occupancy vehicle lanes; except that no fewer than 2 occupants per vehicle may be
required.”
Federal guidance for the design of HOV facilities is provided in the American
Association of State Highways and Transportation Officials ( AASHTO) Guide for the
Design of High- Occupancy Vehicle Facilities6. Further guidance for the design and
operation of HOV facilities is provided in the Transportation Research Board ( TRB)
Report 414: HOV Systems Manual7. In general, the AASHTO standards require HOV
lanes to be a minimum of 12 feet in width, with a 10 foot inside shoulder. The Federal
Highway Administration ( FHWA) requires all HOV facilities to be developed to AASHTO
standards unless a design exception is granted.
FHWA policy requires the review and approval of any significant operational change to
an HOV facility or system. Such changes include an adjustment to the hours of
operation of HOV lanes, or the conversion of HOV lanes to general- purpose lanes. The
Federal- Aid Highway Program Guidance on High Occupancy Vehicle ( HOV) Lanes
addresses the requirements for a detailed review of a proposal to significantly change
the operation of existing HOV lanes, and is included in Appendix B.
In the State of California, the authority to establish HOV lanes is prescribed in § 25485 of
the Public Resources Code, § 149 of the Streets and Highways Code, and § 21655 of the
Vehicle Code. In part, § 21655.5 of the Vehicle Code states that “ the Department of
Transportation and local authorities, with respect to highways under their respective
jurisdictions, may authorize or permit exclusive or preferential use of highway lanes for
high- occupancy vehicles.” Whenever Caltrans authorizes the use of HOV lanes within
the territory of a transportation planning agency, § 21655.6 of the Vehicle Code states
that “ the department shall obtain the approval of the transportation planning agency or
county transportation commission.”
Caltrans Policy and Procedures Memorandum P89- 01 acknowledges that “ a range of
HOV applications may be appropriate for a given freeway segment. The specific
design and operational features will be based on such factors as transportation
demand, timing, costs, safety, maintenance, enforcement needs, funding availability,
environmental considerations, and community support.” The Policy and Procedures
Memorandum assigns responsibility for implementing state HOV policy to the Caltrans
6 Association of State Highways and Transportation Officials, Guide for the Design of High-
Occupancy Vehicle Facilities, 1992
7 Transportation Research Board, Report 414: HOV Systems Manual, National Cooperative
Highway Research Program, 1998.
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HOV Lane Operations Study
District Directors of Transportation in coordination with regional transportation agencies
and under the direction of the Caltrans Chief, Division of Traffic Operations.
In July 1991, the Caltrans Division of Traffic Operations published High Occupancy
Vehicle ( HOV) Guidelines for Planning, Design, and Operations. The Caltrans HOV
Guidelines provides typical scenarios to assist during the planning, design and
operation of HOV facilities. The publication also helps to clarify and expand upon the
intents of the Federal and State statutory requirements and guidelines with regard to
HOV planning considerations, design characteristics and operations policy elements.
The Caltrans HOV Guidelines indicate that the operation of a HOV facility is linked to the
design of the facility, the traffic demand in the freeway corridor, and the geographic
distribution of development and the associated commuter travel patterns in the region.
Having considered these individual elements during the HOV system planning and
facility design phases, the Caltrans HOV Guidelines recommend that the design
features and operational characteristics “ should also be uniform and consistent within a
region.”
In California, the regional HOV systems typically reflect one of two design and
operational variations. In Southern California ( including Los Angeles, Orange, Riverside
and San Bernardino Counties), HOV lanes are typically designed as buffer separated
concurrent flow lanes with limited ingress and egress locations. These lanes typically
operate full- time with a 2+ minimum occupancy requirements. Exceptions to the typical
design and operations characteristics in Southern California include the use of barrier
and/ or grade separated lanes, and the use of increased minimum occupancy
requirements during the peak period.
In Northern California ( including the San Francisco Bay Area), HOV lanes are typically
designed as contiguous concurrent flow lanes with unlimited access. These lanes
typically operate part- time during the peak periods for both directions, and have a 2+
minimum occupancy requirement per vehicle. In select locations, Northern California
HOV lanes operate part- time during the peak periods for the peak direction only, or
require a 3+ minimum vehicle occupancy.
Caltrans explains that HOV design and operations differ throughout the state as a
reflection of different freeway commute patterns. In areas that experience regular
periods of congestion for many hours of the day, full- time HOV operations with
restricted access is favored to maximize opportunities for HOV utilization and travel
time savings, thereby providing incentives to rideshare and relieve the rate of
congestion. Caltrans indicates that routes serving the metropolitan areas of Southern
California often meet and exceed these traffic conditions, substantiating full- time HOV
lane operations and related design elements. Conversely, in areas where commute
patterns generally consist of short definable peak periods and clear directional flows,
part- time, peak period HOV operations are preferred. With part- time operations, the
HOV lanes ideally should look like general purpose lanes to minimize the potential for
motorist confusion when they are open to general- purpose traffic. Accordingly, it is
preferred that access into and out of HOV lanes that operate part time not be restricted.
Caltrans indicates that the metropolitan areas of Northern California typically
Orange County 11 August 1, 2002
HOV Lane Operations Study
experience these traffic characteristics, resulting in the use of part- time HOV lane
operation8.
2.3 Operational Characteristics of the Orange County HOV System
In accordance with State Statutes and Caltrans July 1991 High Occupancy Vehicle
( HOV) Guidelines for Planning, Design, and Operations, all HOV lanes in Orange
County are designed as concurrent- flow, buffer separated lanes with limited ingress
and egress. This policy is consistent with the typical design of HOV lane facilities in the
adjoining counties of the Southern California region, including Los Angeles, Riverside
and San Bernardino Counties. There are a few isolated exceptions to the use of
concurrent flow, buffer separated, limited access facilities in Southern California. These
include segments of I- 10 ( El Monte Busway) constructed outside the freeway median in
a railroad right- of- way and isolated portions of I- 110 ( Harbor Transitway) in Los Angeles
County which is elevated. Segments of the HOV lanes on the I- 5 in Orange County also
include barrier separated and/ or grade separated design treatments, primarily in Santa
Ana where numerous closely spaced freeway ramps and direct access ramps exist.
All designated HOV lanes in Orange County operate full- time ( 24 hours/ 7 days) with a
2+ minimum occupancy requirement per vehicle. In accordance with the latest federal
transportation legislation and § 21655.9 of the California Vehicle Code, motorcycles and
single occupant ultra- low emission vehicles ( ULEV) are also permitted to use all HOV
facilities in Orange County, and throughout the State of California. The operational
characteristics of HOV facilities in Orange County are consistent with that elsewhere in
the Southern California region. There are two exceptions to the HOV operating policy,
with both being in Los Angeles County. These include the I- 10 ( El Monte Busway),
which has had the minimum occupancy requirement increased back to 3+ during
weekday peak periods due to excessive demand, and SR- 14, which operates as a part-time
demonstration HOV facility during peak periods for the peak direction of flow due
to its limited hours of directional congestion.
2.4 Comparative Performance Characteristics of the Orange County HOV
System.
On average, the HOV system in Orange County carries the highest peak hour lane
volumes of any system in California. In 1998, HOV lanes in Orange County carried an
average of 1,568 vehicles per hour ( vph) compared to an average of 1,013 vph in Los
Angeles County and 930 vph in the San Francisco Bay Area. As a point of reference,
the maximum operational capacity of a HOV lane is typically considered to be around
1,650 vph. Figure 2.5 illustrates the average peak hour lane volumes for the six
Caltrans districts with HOV systems.
8 Caltrans Division of Traffic Operations, Statewide High- Occupancy Vehicle Issues – Questions
and Answers ( Memorandum), April 5, 2002.
Orange County 12 August 1, 2002
HOV Lane Operations Study
Figure 2.5 – Average HOV Peak Hour Lane Volumes ( 1998)
Source: Legislative Analyst Office, HOV Lanes in California: Are They Achieving Their
Goals? January 2000
The average peak hour HOV lane volumes in Orange County also reflect high utilization
when compared to facilities elsewhere in North America. Table 2.3 details HOV lane
peak hour volume ranges for HOV systems in a number of cities and states. The peak
hour HOV lane volume for these areas varied from 190 to 1,713 vph, with an overall
average of approximately 1,100 vph9.
Table 2.3 – HOV Peak Hour Lane Volume Ranges
Location HOV Peak Hour Lane Volume
( vph)
Orange County, CA 1,568
Washington, D. C. 663 to 1,713
Texas ( Houston and Dallas) 799 to 1,429
Portland, OR 800 to 900
Washington ( Seattle and Vancouver) 190 to 1,550
Vancouver, B. C. 723
Boston, MA 949
Sources: Legislative Analyst Office, HOV Lanes in California: Are They Achieving Their
Goals? January 2000
Wellander and Leotta, Are High- Occupancy Vehicle Lanes Effective?, 2000
Caltrans HOV Guidelines establish 800 vph as the minimum HOV peak hour lane
volume for a sufficiently utilized HOV lane. In Orange County, all HOV lanes currently
exceed this minimum peak hour volume threshold. Indeed, segments of the I- 5, I- 405
and SR- 55 exceed this threshold by more than double, with peak hour volumes
9 Wellander and Leotta, Are High- Occupancy Vehicle Lanes Effective?, 2000
0
200
400
600
800
1000
1200
1400
1600
Vehicles Per Hour ( vph)
Oakland Sacramento Los
Angeles
San
Bernardino
San Diego Orange
Caltrans District
Orange County 13 August 1, 2002
HOV Lane Operations Study
consistently approaching and exceeding the maximum operational capacity of a HOV
lane thereby leading to intermittent congestion in the carpool lanes. In Orange County,
over utilization of the HOV lanes during peak hours appears to be a major operational
challenge.
Figure 2.6 illustrates peak hour HOV lane volumes for various freeway segments in
Orange County. For comparative purposes, Figures 2.7 and 2.8 illustrate HOV peak
hour lane volumes for freeway segments in Los Angeles County and the San Francisco
Bay Area, respectively. While many facilities in Los Angeles County and the Bay Area
significantly exceed the minimum peak hour lane volume threshold established by
Caltrans, several HOV facilities in each area are either at or slightly below this minimum
threshold. These figures demonstrate that overall, the peak hour carpool lane volumes
in Orange County are consistently high when compared to facilities elsewhere in
California. On average during the peak hours, the HOV system in Orange County is the
most well utilized in the United States.
Orange County 14 August 1, 2002
HOV Lane Operations Study
0
200
400
600
800
1,000
1,200
1,400
1,600
VEHICLES- PER- HOUR- PER- LANE
( VPHPL)
10 WB ( Alameda to Baldwin)
14 SB ( San Fernando to Escondido Cyn)
57 SB ( Orange County to 60)
60 WB ( Brea Canyon to SBD County)
91 WB ( 110 to Orange County)
105 WB ( 405 to 605)
110 NB ( 91 to 105)
110 NB ( 105 to Adams)
118 EB ( Ventura County to 5)
134 WB ( 101/ 170 to 210)
170 SB ( 101/ 134 to 5)
210 NB ( 134 to Sunflower)
405 NB ( Orange County to 110)
405 NB ( 110 to Century)
405 SB ( 101 to 5)
605 SB ( South to 10)
HOV STUDY ROUTES
CARPOOL LANE PEAK VOLUME
( PEAK HOUR - PEAK DIRECTION)
Minimum Threshold
( 800VPHPL)
Figure 2.6 – HOV Peak Hour Lane Volumes in Orange County
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
Figure 2.7 – HOV Peak Hour Lane Volumes in Los Angeles County
Source: Parsons Brinckerhoff Quade and Douglas, HOV Performance Program Evaluation
Report ( Initial Draft), March 2002.
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
VEHICLES- PER- HOUR- PER- LANE ( VPHPL)
I- 5 at Los Alisos
I- 5 at Tustin Ranch
I- 5 at Main
I- 5 at Harbor
I- 5 at Broadway
I- 405 at Von Karman
I- 405 at Ward
SR- 55 at Warner
SR- 55 at Walnut
SR- 57 at Yorba Linda
SR- 91 at Harbor
HOV ROUTE
HOV LANE PEAK VOLUME
( PEAK HOUR - PEAK DIRECTION)
Minimum Threshold
( 800 vphpl)
Orange County 15 August 1, 2002
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Figure 2.8 – HOV Peak Hour Lane Volumes in San Francisco Bay Area
Source: Caltrans District 4, 2001 District 4 HOV Report, February 2002.
The duration of the peak periods on Southern California freeways is longer than that
experienced in the Bay Area, with Southern California freeways typically sustaining high
volumes throughout the day. Similarly, the level of congestion on Orange County
freeways is greater than that observed in Northern California10 and is reflected in the
comparatively high utilization of the Orange County HOV system.
A review of hourly traffic volumes on Orange County HOV lanes shows the relatively
high utilization of the HOV lanes across many hours of the day. During weekdays from
6: 00 AM to 8: 00 PM, the HOV lanes in Orange County typically sustain volumes in
excess of Caltrans minimum peak hour HOV lane volume guideline of 800 vph.
During the typical mid- day off- peak period ( 9: 00 AM to 3: 00 PM), Orange County HOV
lanes continue to carry 35% to 75% of the peak hour HOV lane volumes for the same
route.
Figure 2.9 illustrates combined hourly HOV lane volumes for select routes in Orange
County. For comparison, Figure 2.10 depicts the combined hourly HOV lane
volumes for select freeways in Los Angeles County. These figures illustrate sustained
HOV volumes throughout the day, particularly during the mid- day off- peak period. A
comparison of the figures also highlights the comparatively higher HOV volumes
throughout the day on Orange County freeways, which is consistent with the more
constant bi- directional traffic flows typically observed on Orange County freeways.
10 Joe El Harake, Caltrans District 12 HOV Coordinator, ( Telephone Interview) July 26, 2002.
0
200
400
600
800
1,000
1,200
1,400
1,600
VEHICLES- PER- HOUR- PER- LANE ( VPHPL)
I- 80 at Bay Bridge Toll Plaza
SR- 84 Dumbarton Bridge Toll Plaza
SR- 92 San Mateo Bridge Toll Plaza
I- 880 Marina to Whipple
I- 880 16th to Bay Bridge
I- 80 SR- 4 to Alameda County
I- 680 Livorna to Alcosta
US- 101 SR- 37 to San Pedro
SR- 85 US- 101 to I- 280
US- 101 San Mateo County to Ellis
SR- 237 I- 880 to Mathilda
I- 280 Magdalena to Leland
US- 101 Whipple to Santa Clara County
I- 80 Carquinez Bridge Toll Plaza
HOV ROUTE
HOV LANE PEAK VOLUME
( PEAK HOUR - PEAK DIRECTION)
Minimum Threshold
( 800 vphpl)
Orange County 16 August 1, 2002
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Figure 2.9 – Weekday HOV Hourly Volumes in Orange County
( Thursday, May 16, 2002 – Both Directions Combined)
0
500
1000
1500
2000
2500
3000
3500
1: 00
2: 00
3: 00
4: 00
5: 00
6: 00
7: 00
8: 00
9: 00
10: 00
11: 00
12: 00
13: 00
14: 00
15: 00
16: 00
17: 00
18: 00
19: 00
20: 00
21: 00
22: 00
23: 00
0: 00
Time of Day
Hourly Volume ( vph)
I- 405 at Ward
SR- 55 at Edinger
I- 5 at Main
Source: Caltrans District 12, Traffic Data Report ( unpublished), May 19, 2002
Figure 2.10 – Weekday HOV Hourly Volumes in Los Angeles County
( Typical Weekday April 2000 – Both Directions Combined)
0
500
1,000
1,500
2,000
2,500
3,000
3,500
1: 00
2: 00
3: 00
4: 00
5: 00
6: 00
7: 00
8: 00
9: 00
10: 00
11: 00
12: 00
13: 00
14: 00
15: 00
16: 00
17: 00
18: 00
19: 00
20: 00
21: 00
22: 00
23: 00
0: 00
Time of Day Hourly Volume ( vph)
SR- 60 Brea Cyn to SBD Co.
I- 105 I- 405 to I- 605
I- 405 I- 110 to Century
605 South to I- 10
Source: Parsons Brinckerhoff Quade and Douglas, HOV Performance Program Evaluation Report ( Initial Draft), March 2002.
Orange County 17 August 1, 2002
HOV Lane Operations Study
Sustained hourly HOV volumes are most clearly observed during the weekends on
Orange County freeways, reflecting the popularity of HOV lanes and the effectiveness
of HOV lanes to provide reliable weekend travel times. On both Saturdays and
Sundays, hourly HOV lane volumes in Orange County typically exceed 800 vph from
10: 00 AM to 10: 00 PM, with volumes on most facilities remaining constant between
1,000 vph to 1,300 vph from 11: 00 AM to 7: 00 PM. Figure 2.11 illustrates combined
hourly HOV lane volumes for Sunday traffic on select freeway corridors in Orange
County. This figure clearly shows the relatively high and constant HOV volumes
observed throughout the afternoon and into the evening on weekends.
Figure 2.11 – Weekend HOV Hourly Volumes in Orange County
( Sunday, May 12, 2002 – Both Directions Combined)
0
500
1000
1500
2000
2500
3000
3500
1: 00
2: 00
3: 00
4: 00
5: 00
6: 00
7: 00
8: 00
9: 00
10: 00
11: 00
12: 00
13: 00
14: 00
15: 00
16: 00
17: 00
18: 00
19: 00
20: 00
21: 00
22: 00
23: 00
0: 00
Time of Day
Hourly Volume ( vph)
I- 405 at Ward
SR- 55 at Edinger
I- 5 at Main
Source: Caltrans District 12, Traffic Data Report ( unpublished), May 19, 2002
A review of peak hour directional traffic flows in Orange County HOV lanes reflects a
relatively balanced flow between peak and off peak directions of travel. The relatively
balanced peak hour directional flows in Orange County HOV lanes is consistent with
the continuous high volume bi- directional traffic flows experienced on the grid- like
system of Orange County freeways, and reflects the decentralized nature of land uses
and major employment activity centers in Orange County and the Los Angeles
Metropolitan Area. Figure 2.12 illustrates the PM peak hour directional traffic flows
for select freeway locations in Orange County. The Orange County HOV system is
illustrated previously in Figure 2.3.
Orange County 18 August 1, 2002
HOV Lane Operations Study
Figure 2.12 – PM Peak Hour Directional Traffic Flows in Orange County
Source: Caltrans District 12, Traffic Data Report ( unpublished), May 19, 2002
In contrast to Orange County, peak hour traffic flows in the Bay area reflect a more
directional flow with trips focused primarily on the major employment centers of San
Francisco, Oakland/ Berkeley and San Jose. This directional peak hour traffic flow is
typical of most metropolitan areas and is reflected in the provision of a more radial
freeway system. Figure 2.13 illustrates the PM peak hour directional traffic flow of
HOV lanes on select Bay Area freeways.
- 2000
- 1500
- 1000
- 500
0
500
1000
1500
2000
PM PEAK HOUR DIRECTIONAL VOLUME
I- 5 at Tustin Ranch
I- 5 at Main
I- 5 at Broadway
I- 405 at Von Karman
I- 405 at Ward
SR- 55 at Warner
SR- 57 at Walnut
HOV ROUTE
HOV LANE DIRECTIONAL FLOW
( PM PEAK HOUR)
Off- Peak Direction
Peak Direction
Orange County 19 August 1, 2002
HOV Lane Operations Study
Figure 2.13 – PM Peak Hour Directional Traffic Flows in the San
Francisco Bay Area
Source: Caltrans District 4, 2001 District 4 HOV Report, February 2002.
A fundamental goal of HOV facilities is to maximize the people- carrying capacity of a
freeway corridor. In other words, HOV lanes are intended to carry more people in fewer
cars. Consistent with this fundamental goal, California state law declares that HOV
lanes are “ to encourage individual citizens to pool their vehicular resources.” As a
result, a comparison of person trips between HOV lanes and general- purpose lanes in
a freeway corridor is often used to assess HOV lane performance in accomplishing this
goal.
From 6: 00 AM to 8: 00 PM, the HOV lanes in Orange County consistently carry as many
or more people than the adjacent general- purpose freeway lanes, despite typically
carrying fewer vehicles11. During the peak hours, in many cases the HOV lanes carry
between 150% and 200% of the people that are being carried in the adjacent general-purpose
lanes fulfilling the fundamental goal of carrying more people in fewer cars.
Figure 2.14 provides a comparison of PM peak hour person trips in the HOV lanes
and general- purpose lanes for HOV corridors in Orange County.
11 Joe El Harake, Caltrans District 12 HOV Coordinator, ( Telephone Interview) July 26, 2002.
- 1500
- 1000
- 500
0
500
1000
1500
PM PEAK HOUR DIRECTIONAL VOLUME
I- 80 Contra Costa County to Powell
I- 880 Marina to Whipple
I- 80 SR- 4 to Alameda County
I- 680 Livorna to Alcosta
SR- 85 US- 101 to I- 280
US- 101 San Mateo County to Ellis
SR- 237 I- 880 to Mathilda
I- 280 Magdalena to Leland
US- 101 Whipple to Santa Clara County
HOV ROUTE
HOV LANE DIRECTIONAL FLOW
( PM PEAK HOUR)
Off- Peak Direction
Peak Direction
Orange County 20 August 1, 2002
HOV Lane Operations Study
Figure 2.14 – PM Peak Hour Person Trips for HOV Corridors in Orange
County
Source: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
The generally higher person- carrying capabilities of HOV lanes are also reflected in the
comparison of person trips observed in Los Angeles County and the San Francisco Bay
Area HOV corridors. In several locations, HOV lanes in Los Angeles County and the
Bay Area are carrying a higher number of person trips than any of the HOV lanes in
Orange County. For these locations, greater transit utilization and increased minimum
occupancy requirements typically influence the utilization rate. However, at other
locations in these areas, the HOV lanes are not carrying more person trips than the
adjacent general- purpose lanes reflecting inconsistencies in area lane performance.
Figures 2.15 and 2.16 illustrate HOV peak hour person trips for facilities in Los
Angeles County and the San Francisco Bay Area, respectively.
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
PERSON TRIPS PER LANE ( PTPL)
I- 5 at Los Alisos
I- 5 at Tustin Ranch
I- 5 at Main
I- 5 at Harbor
I- 5 at Broadway
I- 405 at Von Karman
I- 405 at Ward
SR- 55 at Warner
SR- 55 at Walnut
SR- 57 at Yorba Linda
SR- 91 at Harbor
HOV ROUTE
PERSON- TRIPS
( PM PEAK HOUR - PM PEAK DIRECTION)
HOV Lanes
Other Lanes
Orange County 21 August 1, 2002
HOV Lane Operations Study
Figure 2.15 – PM Peak Hour Person Trips for HOV Corridors in Los
Angeles County
Source: Parsons Brinckerhoff Quade and Douglas, HOV Performance Program Evaluation
Report ( Initial Draft), March 2002.
Figure 2.16 – Peak Hour Person Trips for HOV Corridors in the San
Francisco Bay Area
Source: Caltrans District 4, 2001 District 4 HOV Report, February 2002.
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
PERSON- TRIPS- PER- LANE ( PTPL)
10 EB ( Alameda to Baldwin)
14 NB ( San Fernando to Escondido Cyn)
57 NB ( Orange County to 60)
60 EB ( Brea Canyon to SBD County)
91 EB ( 110 to Orange County)
105 EB ( 405 to 605)
110 SB ( 91 to 105)
110 SB ( 105 to Adams)
118 EB ( Ventura County to 5)
134 EB ( 101/ 170 to 210)
170 NB ( 101/ 134 to 5)
210 EB ( 134 to Sunflower)
405 SB ( Orange County to 110)
405 SB ( 110 to Century)
405 NB ( 101 to 5)
605 NB ( South to 10)
CONTROL ROUTES
5 SB ( 605 to 710)
101 NB ( 405 to 27)
HOV STUDY ROUTES
PERSON- TRIPS
( PM PEAK HOUR - PM PEAK DIRECTION)
Carpool Lanes
Other Lanes
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
PERSON TRIPS PER LANE ( PTPL)
I- 80 at Bay Bridge Toll Plaza
SR- 84 Dumbarton Bridge Toll Plaza
SR- 92 San Mateo Bridge Toll Plaza
I- 880 Marina to Whipple
I- 880 16th to Bay Bridge
I- 80 SR- 4 to Alameda County
I- 680 Livorna to Alcosta
US- 101 SR- 37 to San Pedro
SR- 85 US- 101 to I- 280
US- 101 San Mateo County to Ellis
SR- 237 I- 880 to Mathilda
I- 280 Magdalena to Leland
US- 101 Whipple to Santa Clara County
I- 80 Carquinez Bridge Toll Plaza
HOV ROUTE
PERSON- TRIPS
( PM PEAK HOUR - PM PEAK DIRECTION)
HOV Lanes
Other Lanes
Orange County 22 August 1, 2002
HOV Lane Operations Study
Minimum occupancy violation rates in Orange County HOV lanes are among some of
the lowest in the nation, with peak period violation rates ranging from 0.1% to 1.5% by
facility segment12. Preserving low HOV violation rates is particularly important in areas
where HOV lanes are highly utilized. By maintaining low violation rates, the full capacity
in the HOV lane can be provided for HOV lane users, thereby ensuring maximum travel
time savings and trip reliability. Significant increases in the number of HOV lane
violators would effectively “ steal’ capacity from HOV users, and could result in
congestion in the HOV lanes should volumes start to exceed operational capacity.
The peak period violation rates in Orange County tend to be consistent with peak
period violation rates observed in Los Angeles County, with the exception of the I- 10 ( El
Monte Busway). Peak period violations on the I- 10 ( El Monte Busway range from 4.6%
during the AM peak to 11.2% during the PM peak. The significantly higher violation
rates on the El Monte Busway appear indicative of HOV lane user confusion of the
recently reverted increased minimum occupancy requirement during the peak periods.
Peak period violations rates elsewhere on the Los Angeles County HOV system range
from 0.0% to 1.3%, which is consistent with the experience in Orange County13.
Peak period violation rates in the San Francisco Bay Area vary greatly, with rates
ranging from 0.2% to 24.5%, with most facilities experiencing violation rates in excess
of 3.0% 14. The overall higher minimum occupancy violation rates in the Bay Area are
most likely attributable to the variable hours of operation, disparate minimum
occupancy requirements, and the use of continuous HOV lane access.
Table 2.4 provides a sample of PM peak period HOV lane violation rates for facilities
in Orange County, Los Angeles County and the San Francisco Bay Area.
12 Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
13 Caltrans District 7, 2001 HOV Annual Report, May 2002.
14 Caltrans District 4, 2001 District 4 HOV Report, February 2002.
Orange County 23 August 1, 2002
HOV Lane Operations Study
Table 2.4 – PM Peak Period HOV Lane Violation Rates
Orange County Los Angeles County San Francisco Bay Area
Location Violation
Rate Location Violation
Rate Location Violation
Rate
I- 5 at Los Alisos 0.2% I- 10 at Jackson 11.2% I- 80 at Bay Bridge Toll Plaza 9.8%
I- 5 at Tustin Ranch 0.3% SR- 14 at Golden Valley 0.1% SR- 84 Dumbarton Bridge 2.2%
I- 5 at Main 0.5% SR- 57 at Pathfinder 0.3% SR- 92 San Mateo Bridge 5.4%
I- 5 at Harbor 0.1% SR- 60 at Phillips Ranch 0.1% I- 880 Marina to Whipple 3.9%
I- 5 at Broadway 0.2% SR- 91 at Wilmington 0.3% I- 880 16th to Bay Bridge 14.6%
I- 405 at Von Karman 0.3% SR- 91 at Artesia 0.0% I- 80 SR- 4 to Alameda County 4.4%
I- 405 at Ward 0.2% I- 105 at Long Beach 0.6% I- 680 Livorna to Alcosta 5.0%
SR- 55 at Warner 0.2% I- 110 at Slauson 0.4% US- 101 SR- 37 to San Pedro 1.1%
SR- 55 at Walnut 0.7% SR- 118 at Reseda 0.2% SR- 85 US- 101 to I- 280 0.4%
SR- 57 at Yorba Linda 0.4% SR- 134 at Jackson 0.0% US- 101 San Mateo Co. to Ellis 3.2%
SR- 91 at Harbor 0.4% SR- 170 at Sherman 0.0% SR- 237 I- 880 to Mathilda 2.1%
I- 210 at Wilson 0.3% I- 280 Magdalena to Leland 1.0%
I- 210 at Second 0.1% US- 101 Whipple to Santa Clara Co. 7.0%
I- 405 at Normandie 0.0% I- 80 Carquinez Bridge Toll Plaza 1.2%
I- 405 at Burbank 0.4%
I- 605 at Beverly 0.1%
Sources: Caltrans District 12, 2001 District 12 Annual HOV Report, May 2002.
Caltrans District 7, 2001 HOV Annual Report, May 2002.
Caltrans District 4, 2001 District 4 HOV Report, February 2002.
Orange County 24 August 1, 2002
HOV Lane Operations Study
3.0 Developing HOV Operating Policy In Orange County
The Orange County HOV system’s operation policies have been in place since 1985
and evolved based on a series of demonstrations undertaken by Caltrans in
conjunction with local transportation agencies including the Orange County
Transportation Commission ( OCTC), the predecessor agency for OCTA. Specifically,
these demonstrations included HOV lanes implemented in 1984 on 10 miles of SR- 91
( Artesia Freeway) in Los Angeles County and in 1985 on 12 miles of SR- 55 ( Costa Mesa
Freeway) in Orange County. These initial projects followed the development of the I- 10
( El Monte Busway) in Los Angeles County, but each differed from current HOV lanes in
a variety of respects. The eastbound SR- 91 operation was initially opened for peak
periods only, using the pavement occupied by the inside shoulder. SR- 55 opened with
narrow lanes and no buffer separation. Operation experience from both projects
helped to shape the HOV policies in place throughout the four- county Southern
California region today.
Part- time operation on SR- 91 revealed that motorists became confused when the HOV
lane reverted back to an emergency breakdown shoulder. In 1986 the initial peak-period
operating period was extended to 24 hours in order to meet growing off- peak
directional demand, to reduce motorist confusion, and to make the project more
consistent with I- 10 and SR- 5515.
Safety concerns raised by Drivers for Highway Safety, an Orange County highway
advocacy group, resulted in the enactment of Senate Bill ( SB) 699 and an amendment
to the California Vehicle Code to add a four- foot buffer on SR- 55. This buffer was
incorporated as part of freeway widening work already underway. While SR- 55 always
had designated ingress/ egress areas, these areas were refined and improved as part
of the addition of buffers.
In both cases, advisory groups were established to help key agency stakeholders
shape operation policies that emerged. For the SR 55 project, the advisory group
included:
t Orange County Transportation Commission ( now OCTA)
t Orange County Transit District ( now OCTA)
t City of Orange
t City of Anaheim
t City of Santa Ana
t City of Costa Mesa
t City of Tustin ( mayor chaired the advisory group)
t City of Irvine
t Orange County Board of Supervisors
t California Highway Patrol ( CHP)
t Industrial League
t Association of Commuter Transportation
15 Texas Transportation Institute, HOV Project Case Studies: History and Institutional
Arrangements, December 1990.
Orange County 25 August 1, 2002
HOV Lane Operations Study
t Automobile Club of Southern California
t Orange County Chamber of Commerce
t Southern California Association of Governments ( SCAG)
t Area legislators
Key stakeholder collective concurrence on these policies, reinforced with ongoing
Caltrans monitoring, and periodic safety and operational studies conducted by OCTA,
helped shape and institutionalize a 24- hour operation policy and restrictions on access
to the HOV lanes. Key considerations related to a 24- hour operation policy were:
t Consistency with other projects in adjoining counties,
t High levels of use during daytime hours, including mid- day, and
t Safety of operations.
Periodic re- assessments of the 24- hour operation policy have been undertaken by
OCTA in 1991 and 1999. The December 1991 Orange County High Occupancy
Vehicle Lanes Hours of Operation Study helped re- confirm the basis for this operation
policy. In the intervening years, the level of carpool lane use has increased to the point
of over- saturation in some segments, resulting in a net decline in HOV lane traffic
volumes according to Caltrans District 12 traffic data.
The development of designated ingress/ egress policy was due to the severe
congestion observed for many hours each day and the high levels of HOV lane use.
These conditions created major weaving conflicts that could only be alleviated with
direct access ramps and designated access locations. The HOV lane system is
essentially an express lane system primarily intended to serve longer distance
commute trips. To curtail some local HOV demand and to help maintain a higher level
of service and a higher level of demand, access was restricted to better manage flow
rates in the HOV lanes.
These findings observed very early in the development of Orange County’s carpool
lane system helped confirm time of day operation and an access design that best
suited the high reliance commuters placed on these lanes. The demonstration of HOV
lanes on SR- 55 and elsewhere in the Southern California region served as the template
for the subsequent development of the regional HOV system and the evolution of
regional HOV operational policy.
Orange County 26 August 1, 2002
HOV Lane Operations Study
4.0 Hours of Operations
The TRB HOV Systems Manual16 states, “ in general, the operating hours of HOV
facilities can be categorized by three different scenarios. These are continuous 24-
hour use, extended morning and afternoon operation hours, and peak- period only
operation.” The latter two scenarios are also categorized as part- time operations.
Factors influencing HOV operating hours, according to the HOV Systems Manual,
“ include the project goals and objectives, the type of HOV facility, the level of
congestion in the corridor, system of regional connectivity, and enforcement and safety
concerns.” This section of the report discusses regional policy variations across three
regions with contrasting hours of operation policies; summarizes general “ advantages
and disadvantages” of each type of operating policy; and discusses the factors to be
considered when determining the appropriate operating schedule for HOV facilities.
4.1 Regional Policy Variations
To assess a range of time of day operating policies, three separate regions are looked
at and assessed for comparison with Orange County: Los Angeles County, the San
Francisco Bay Area, and the Seattle Central Puget Sound Region. The three systems
are representative of systems similar is size to that in Orange County, but encapsulate
the extremes of the range of time of day HOV operations.
4.1.1 Los Angeles County
Los Angeles County, currently with 383 HOV lane- miles in service17, generally has the
same operating policy as Orange County, with 24- hour per day, 7 days per week
operation and buffer- separated HOV facilities. The 24- hour operation policy has been
determined to be most appropriate for Los Angeles County facilities due to the long
hours of congestion experienced on area freeways. Additionally, in a recent interview
with Lt. Richard Rennie of the California Highway Patrol officer, it was the opinion of Lt.
Rennie that a 24- hour policy would not only be easier to enforce, but outside congested
hours general- purpose traffic does not need to use the HOV lane anyway. 18
The lone exception to the hours of operation policy is SR- 14, which is currently being
operated part- time during the peak- hour in the peak direction of flow as a
demonstration project. Unlike most other Los Angeles County freeways, SR- 14 typically
experiences congestion only during peak periods and in the peak direction.
Additionally, this facility is isolated from the rest of the Los Angeles County HOV
system. For these reasons, the SR- 14 represents a suitable corridor to serve as a
demonstration of the impact of part- time operations on a limited ingress/ egress, buffer
separated HOV facility. The SR- 14 HOV lanes, constructed with a four- foot buffer
separation, are intended to eventually return to 24- hour operation. This reversion will
likely occur before 2008, when Caltrans plans to connect the SR 14- HOV lanes directly
with the proposed HOV lanes on I- 5. At that point, given a direct connection with the
16 Transportation Research Board, Report 414: HOV Systems Manual, National Cooperative
Highway Research Program, 1998.
17 Caltrans District 7, 2001 HOV Annual Report, May 2002.
18 Lt. Richard Rennie, California Highway Patrol, ( Telephone Interview) July 26, 2002.
Orange County 27 August 1, 2002
HOV Lane Operations Study
rest of the Los Angeles County HOV system, the SR 14 lanes will operate on a
consistent schedule because “ both Caltrans and the California Highway Patrol believe
that allowing any HOV lanes in the system to operate on different hours than the rest of
the system can cause driver confusion, increase HOV lane violations, and impair traffic
flow and safety.” 19
4.1.2 San Francisco Bay Area
There are currently 274.5 HOV lane- miles in use in the San Francisco Bay Area20. The
hours of operation are Monday through Friday part- time with actual times varying
depending on the specific characteristics of the facility. The AM period ranges from a
minimum length of two hours ( 6: 30 AM to 8: 30 AM) to a maximum length of five hours
( 5: 00 AM to 10: 00 AM). The PM period ranges from three hours ( 3: 00 PM to 6: 00 PM) to
four hours ( 3: 00 PM to 7: 00 PM) in length. All of the Bay Area HOV lanes are
concurrent flow lanes with continuous ingress/ egress operations. The 1991 Orange
County HOV lane hours of operation report21 states, “ in Northern California it was felt
that the public would be more receptive to a peak- period only operation. This
consideration was based largely upon low traffic volumes and short congestion
periods.” Recent discussions with Bay Area transportation officials22 indicate that this is
still the case, and that the short congestion periods are consistent with the fact that
many of the facilities in the Bay Area are radially oriented toward the major employment
centers of downtown San Jose, Oakland and San Francisco, tending to generate high
concentrations of trips in the peak periods. Figure 4.1 illustrates the pattern of HOV
facilities in the San Francisco Bay Area.
Currently the part- time hours of operation policy appears to work well in the Bay Area,
and recent surveys indicate that both HOV users and non- users are generally happy
and accepting of the HOV lanes. There has been no move recently to try and change
the operating policy in the San Francisco Bay Area to full- time HOV operations.
19 Legislative Analyst Office, Effects of Part- Time Operation: HOV Lanes on Route 14, April
2002.
20 Caltrans District 4, 2001 District 4 HOV Report, February 2002.
21 Orange County Transportation Authority, Orange County High Occupancy Vehicle Lanes
Hours of Operation Study, December 1991.
22 Doug Kimsey, Metropolitan Transportation Commission, ( Telephone Interview), July 24, 2002
Orange County 28 August 1, 2002
HOV Lane Operations Study
Figure 4.1 – San Francisco Bay Area HOV System
Source: Caltrans District 4, 2001 District 4 HOV Report, February 2002.
Orange County 29 August 1, 2002
HOV Lane Operations Study
4.1.3 Seattle/ Central Puget Sound Region
The central Puget Sound region in Washington State currently has 198 HOV lane- miles
in operation. All of these, except for two reversible lane facilities, operate on a 24- hour
7 days per week basis. However, unlike Southern California HOV lanes, except for the
reversible facilities, these lanes are designed as concurrent flow lanes with a single
solid white painted stripe separation allowing continuous ingress/ egress operations.
The current full- time HOV lane operation policy was originally established with the
support of the Washington State Patrol for consistent enforcement purposes. At the
time, the patrol was concerned about increased speeds in the HOV lanes during off-peak
hours and it was felt that the added traffic in the HOV system was unnecessary as
the general- purpose lane capacity was adequate during these off- peak hours23.
More recently, the freeway system in the Seattle region is experiencing much longer
hours of heavy congestion. Segments of I- 5 in downtown Seattle now operate over
capacity up to 13 hours a day and the HOV system is used by a large number of
multiple occupant vehicles throughout the day. Drivers in the Puget Sound Region are
encouraged to carpool all day instead of just during traditional " rush hour" 24,
substantiating the current full- time HOV lane operations.
However, over the past decade, each Washington State legislative session has
generated one or more proposals for eliminating freeway HOV lanes or reducing HOV
lane operational hours. Each time policy and operational reviews by the Washington
State Transportation Commission, the Washington State Department of Transportation
( WSDOT), and the Puget Sound Regional Council’s HOV Policy Advisory Committee
have strongly concluded that the 24- hour policy remains warranted. Most recently, the
Secretary of Transportation has asked WSDOT staff to assess the appropriateness of
the current hours of operation policy. A decision based on this latest evaluation is
expected possibly as early as the fall of 2002. To support this decision, WSDOT is
collecting information related to safety and freeway operations, environmental impact,
public attitudes, impact on transit, carpools and vanpools, and legal and regulatory
obligations and impacts. WSDOT has created a website where the evaluation data can
be found at http:// www. wsdot. wa. gov/ hov/ pugetsoundeval/ default. cfm.
In past assessments, the 24- hour, 7 days a week policy has been addressed by
transportation officials using traffic data from an ongoing HOV performance monitoring
program. The 24- hour policy has been upheld primarily for the following reasons:
t The peak period on many area freeways is expanding to many hours out of the
day, and in times where congestion is not occurring, additional capacity for
general- purpose traffic is not needed as well.
t Many of the HOV lanes are considered “ substandard” because they were
retrofitted to the existing highway system.
t A 24- hour lane operation policy is much clearer for the motorist, and easier for
the Washington State Patrol to enforce.
23 John O'Laughlin, former Washington State Patrol Officer, ( E- mail Interview), July 29, 2002
24 John O'Laughlin, former Washington State Patrol Officer, ( E- mail Interview), July 29, 2002
Orange County 30 August 1, 2002
HOV Lane Operations Study
t Transit agencies relying on the lanes to maintain schedules have objected
strongly to part- time operations.
t Opening the lanes at times to general- purpose traffic could actually make traffic
worse in some locations. HOV lanes do not run continuously on many freeways,
and if more vehicles were in those lanes traffic would slow considerably as
drivers try to merge into general- purpose lanes where those lanes end.
It should be noted that outside of the Puget Sound region, one other HOV lane exists in
the State of Washington. The Vancouver HOV lane on I- 5 in southwest Washington was
opened in September 2001 as a peak period, peak direction facility to facilitate
southbound traffic into Portland, Oregon, bypassing the peak period bottleneck caused
at the Columbia River Bridge. The reasons this facility is operated on a part- time basis
are because 1) it ties into a part- time facility on the Oregon side of the river, 2) it is a
relatively short facility designed primarily to bypass a specific bottleneck, and 3)
congestion is limited to relatively short periods of duration as compared to the Central
Puget Sound region.
4.2 Advantages and Disadvantages
Based on a review of HOV systems around the country, and the most recent HOV
related literature, general “ advantages and disadvantages” of full- time hours of
operations versus part- time HOV operations are summarized in Table 4.1.
Orange County 31 August 1, 2002
HOV Lane Operations Study
Table 4.1 – Advantages and Disadvantages of Full- Time Versus Part- Time HOV Hours of
Operation
Criterion Full- Time ( 24 Hour) Operations
Part- Time Operations
( with general- purpose use of lanes during
other times)
Travel Time
Savings
¨ Potential for HOV travel time savings
whenever congestion is present in the
general- purpose lanes
¨ Potential for HOV travel time savings only during
periods of part- time operation.
¨ No impact if midday traffic is uncongested.
Trip Reliability ¨ High level of HOV travel time reliability
throughout the day regardless of
conditions in the general- purpose lanes.
¨ Provides HOV travel time reliability only during
periods of part- time operation.
¨ No impact if midday traffic is uncongested.
Person Carrying
Capacity/
Throughput
¨ Maintains option for high person carrying
capacity and throughput at all times.
¨ Facilitates higher levels of person
throughput throughout the day.
¨ Facilitates higher levels of person throughput during
part- time operations only.
¨ Facilitates higher levels of vehicular throughput during
periods of general- purpose use of lane.
Enforcement ¨ Simplifies “ enforceability” by eliminating
confusion over how and when the lanes
can be used.
¨ Enforcement costs may be higher due to
the need for ongoing enforcement.
¨ Potential confusion on the part of motorists may
contribute to higher violations ( particularly near the
beginning or end of the part- time operation).
¨ Increases the difficulty of enforcement.
Adjoining HOV
Facilities/ Systems
¨ “ A uniform policy for hours of operation is essential for a corridor and desirable for a region.” 25
¨ If adjoining facilities, or even neighboring regions, have contrasting hours of operation policies, then
motorist confusion, violation rates and enforcement difficulties are likely to increase.
Safety ¨ HOV facilities are often granted design exceptions ( e. g., minimal shoulders, narrower lanes, or left side
ramps) based on the expectation that they would generally experience lower vehicular volumes than a
general- purpose lane.
¨ Allowing general- purpose use, and presumably higher volumes, on these facilities during “ off- peak”
times may be a safety concern.
Transit Operations ¨ Facilitates transit speed and reliability
throughout the day.
¨ Facilitates transit speed and reliability during the part-time
operations period only.
General- Purpose
Operations
¨ Does not provide additional capacity for
general- purpose traffic at any time of the
day.
¨ Provides additional capacity for general- purpose
traffic during the off- peak.
¨ Most beneficial to traffic during the “ shoulders” of the
peak, and during times of unexpected congestion
such as during incidents or special events.
Ingress/ Egress
Policy
¨ Conducive to limited ingress/ egress
operations ( e. g., buffer or barrier
separated facilities with designated
ingress/ egress points), but also has been
shown to work with unlimited open
ingress/ egress operations.
¨ Most compatible with unlimited ingress/ egress
operations and contiguous HOV lanes skip- striped
similarly to other general- purpose lanes.
¨ Part- time operations on a buffer- separated facility with
limited ingress/ egress points may cause motorist
confusion, safety and enforcement concerns.
Direct Access
Facilities
¨ Compatible with an HOV “ system”,
including use of direct access ramps to
the arterial system, and direct connector
ramps at interchanges.
¨ May necessitate the limitation or elimination of the use
of some types of HOV direct access facilities, such as
left- side drop ramps or connector ramps that were
designed and approved for volumes indicative of
HOV- only use.
¨ If general purpose traffic is allowed to use left- side
ramps, undesirable left- to- right side weaving could
result.
Signing and
Pavement
Markings
¨ Simplifies signing and pavement
markings. 26
¨ Requires additional signing and/ or pavement marking
for clarification of part- time operations.
Public Perception ¨ Can encourage off- peak ridesharing and
transit use.
¨ Possible negative public perception if the
facility is not well used during off- peak
times.
¨ Does not encourage off- peak ridesharing or transit
use.
¨ Reduces potential for public perception of “ empty
lane” syndrome during off- peak times.
25 Fuhs, Charles A., High- Occupancy Vehicle Facilities: A Planning, Design, and Operation
Manual, December 1990.
26 Transportation Research Board, Report 414: HOV Systems Manual, National Cooperative
Highway Research Program, 1998.
Orange County 32 August 1, 2002
HOV Lane Operations Study
4.3 Evaluation Criteria
Factors to consider when evaluating the appropriate hours of operation policy for a
given HOV facility are numerous. Typically these factors relate to the desired goals
and objectives that the HOV facilities are intended to achieve, as stated by the
implementing agencies. Typical objectives of HOV facilities include27:
t Increasing the average number of persons per vehicle in travel corridor ( key
factors for achieving this objective are further identified as providing travel time
savings and travel time reliability to HOV users),
t Preserving the person- movement capacity of the roadway, and
t Enhancing bus transit operations.
Additional factors in support of these objectives include effective utilization and
effective enforcement of the facility. Given these objectives, as well as the advantages
and disadvantages outlined above, key factors to consider with respect to determining
HOV hours of operation are discussed in the following sections.
4.3.1 HOV and Transit Travel Time Savings and Trip Reliability
t Both travel time savings and trip time reliability are critical benefits to HOV lane
users. Travel time savings due to 24- hour HOV designation is dependent on the
presence of midday congestion. Trip time reliability is key whether there is regular
or sporadic congestion in the general- purpose lanes.
While it has long been noted that travel time savings was a primary benefit of HOV
lanes, trip reliability is becoming recognized more and more as an equally key benefit
of effective HOV facilities. Being able to consistently predict how long a given trip will
take is valuable to the HOV lane user for many reasons, including enabling them to plan
and schedule their time more effectively. Recent HOV performance monitoring
programs in Los Angeles and Seattle have included trip reliability measures as part of
their evaluation of the effectiveness of HOV lanes. While this measure is often viewed
as most critical during the peak period, it is also important during off- peak times.
In locations where mid- day or weekend congestion is infrequent, maintaining off- peak
operations of a HOV lane is not as critical to maintaining trip reliability. However, in
regions where congestion extends into the mid- day hours on either a regular or
sporadic basis, maintaining HOV lane operations is key to maintaining reliable travel
times for HOV lane users. Regardless of whether congestion occurs in the general-purpose
lanes, the availability of HOV lanes ensures users that they can depend on
consistently taking the same amount of time to reach a given destination.
27 Transportation Research Board, Report 414: HOV Systems Manual, National Cooperative
Highway Research Program, 1998.
Orange County 33 August 1, 2002
HOV Lane Operations Study
Traffic congestion on HOV lane corridors in Orange County can occur at any time of
day, not just during the traditional “ peak periods”. The 1991 OCTA Hours of Operation
Study indicated that the combined AM and PM peak periods on various Orange County
freeways ranged from 4 hours ( SR- 22 West) to 13 hours ( I- 5 North), with the typical
peak spreading across 8 to 10 hours. A review on annual traffic growth on these
facilities shows that traffic in Orange County has grown up to 35% percent in some
locations between 1991 and 2001, indicating that the congestion has worsened and the
peak hours have likely spread further than the 1991 levels. Operating HOV lanes
throughout the day helps ensure that Orange County HOV users maintain trip time
reliability, and travel time savings when general- purpose lanes become congested.
4.3.2 Regional Consistency
t “ A uniform policy for hours of operation is essential for a corridor and desirable for a
region.” 28 If adjoining facilities, or even neighboring regions, have contrasting hours
of operation policies, then motorist confusion, violation rates and enforcement
difficulties are likely to increase.
A decision to change the hours of HOV lane operation on any one facility, or for the
entire Orange County HOV system, would need to be assessed in conjunction with its
impact to neighboring county HOV systems. Los Angeles County, San Bernardino
County and Riverside County HOV lanes all operate 24- hour, 7 days a week, with the
exception of an isolated segment of SR- 14, which is currently operating part- time as a
demonstration project. Because of this, either the other counties will need to revise
their operating rules or lane transitions will need to be added to allow other traffic to
escape/ enter HOV lane at the County line during times of general- purpose use of the
lanes in Orange County. Additionally, increased off- peak direction capacity may create
queuing and associated congestion where general- purpose lane drops occur when
leaving Orange County.
28 Fuhs, Charles A., High- Occupancy Vehicle Facilities: A Planning, Design, and Operation
Manual, Parsons Brinckerhoff, December 1990.
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HOV Lane Operations Study
4.3.3 HOV Facility Type
t The orientation and design of an HOV facility may influence hours of operation. 29
For example, facilities designed to provide a bypass around a specific bottleneck
may operate only during specific time periods; however, a regional system with
relatively high levels of congestion throughout is likely to be necessary for longer
durations.
All of Orange County’s HOV lanes are designed to provide HOV mobility throughout a
system of congested freeways, rather than as bypasses of specific bottleneck
locations, warranting a continuation of the current hours of operation policy based on
this factor
4.3.4 Safety and Operations
t Primary safety issues relate to higher general- purpose traffic volumes using limited
access, buffer- separated lanes, as well as the associated HOV direct access ramps
and freeway- to- freeway connectors during general- purpose use of the HOV lane.
Additional concerns include higher traffic volumes weaving at the limited
ingress/ egress locations.
HOV facilities often involve the use of design exceptions to make it possible to
implement these facilities in constrained corridors. The decision to allow design
exceptions is often based on the reduced level of traffic demand associated with HOV
lanes. The impact of additional traffic volumes in HOV lanes represents primary safety
and operational considerations. Before an operation change is made, a careful
analysis is required to determine whether design deviations must be revisited, or
physical improvements made to accommodate general- purpose volumes.
In Orange County, operational and safety design considerations are particularly
pertinent given the relatively high number of left- side HOV direct access ramps and
HOV freeway- to- freeway direct connector ramps, and the high general- purpose traffic
volumes over extended periods of the day. Operation of these facilities with general-purpose
use of the HOV lane may create unsafe conditions, especially if general-purpose
traffic is allowed to use left- side direct access ramps, because additional
weaving movements could be induced across all traffic lanes.
Because of the double yellow line lane striping in the buffer, the limited ingress/ egress
operations would be enforced for general- purpose traffic outside of the peak period
HOV lane operations. This limits the ability of general- purpose traffic to fully utilize the
HOV lane as compared to a regular general- purpose lane. Assuming that the HOV lane
buffers remain, along with designated ingress/ egress access to the lane, an
assessment of the potential operational limitations for general- purpose use of the HOV
lanes in Orange County would need to be conducted prior to a change in HOV hours of
operation.
29 Transportation Research Board, Report 414: HOV Systems Manual, National Cooperative
Highway Research Program, 1998.
Orange County 35 August 1, 2002
HOV Lane Operations Study
4.3.5 Impact on Enforcement
t Potential confusion on the part of motorists may contribute to higher violations
( particularly near the beginning or end of the part- time operation), and increase the
difficulty of enforcement.
Orange County currently experiences extremely low HOV lane violation rates ( 0.1% to
0.7%). Preserving low violation rates ensures that the maximum HOV lane capacity is
available to HOV users, thereby providing the maximum time savings and trip reliability
on highly utilized HOV facilities. Changing operations to part- time would most likely
increase violation rates due to the increased confusion on the part of motorists,
particularly near the beginning or end of the part- time operation. Changes in the hours
of operation would also increase the difficulty of enforcement.
The San Francisco Bay Area part- time HOV lanes currently experience violation rates
ranging up to 14.6%. This higher violation rate is most likely due to the combination of
part- time operations and the use of continuous ingress/ egress operations. Law
enforcement officials in both Southern California and Washington State have indicated
that 24- hour HOV facilities are easier to effectively enforce as compared to part- time
facilities.
4.3.6 FHWA Approval and Potential Fund Restrictions
t According to current FHWA HOV guidelines30, switching from 24- hour HOV lane
operation to only a portion of the day or week qualifies as a significant operational
change requiring FHWA review and approval.
FHWA must be consulted if a proposed significant operational change can be
reasonably expected to affect a specific HOV lane or portions of the regional HOV
system that was funded and/ or approved by FHWA. A change from 24- hour to part-time
HOV operations in Orange County would require FHWA review and approval.
A major question would be the continued operations of the existing HOV drop ramps
and freeway connectors. Based on recent precedent in federal policy guidance
forwarded to Washington State regarding the Puget Sound HOV system, FHWA will
likely require that all left side direct access ramps be closed or gated to prohibit use to
general- purpose traffic during the periods when they are not in use by HOV traffic.
There are a large number of high volume direct access ramps in Orange County that
are potentially impacted by this issue. FHWA approval of these operation changes is
required, or federal funding for past and future projects will be at risk.
The closing of direct access ramps and freeway- to- freeway connectors would be
exacerbated by the lack of alternative ingress/ egress locations ( particularly along the I-
5 corridor) and the apparent inconsistency of existing HOV lane signage that would
incorrectly indicate the availability of an HOV ingress/ egress location during off peak
hours. In order to fulfill any FHWA requirement to close or gate left side access ramps,
30 Federal Highway Administration, Program Guidance on High Occupancy Vehicle Lanes,
( Memorandum) March 2001
Orange County 36 August 1, 2002
HOV Lane Operations Study
alternative ingress/ egress locations and variable replacement signage would be
necessary.
4.3.7 Public Attitudes/ Perception
t Opening HOV lanes to general- purpose use during portions of the day may reduce
negative public perceptions such as the “ empty lane syndrome.” However, the
provision of HOV lanes creates an incentive for ridesharing and transit use outside
of typical commute periods.
Given the relatively high traffic volumes in Orange County, public perception of the
“ empty lane syndrome” is likely to be less than in most other regions, effectively
eliminating the consideration to change hours of HOV lane operation as a response to
public opinion. However, the potential for travel time savings for HOV users throughout
the day due to the extended hours of congestion may serve to induce additional
ridesharing and/ or transit use, justifying the continuation of the current lane operation
policy.
4.3.8 Cost
t Changing the hours of HOV operation would result in added costs necessary to
change the current HOV signage, and possibly striping depending on whether the
designated ingress/ egress operations are changed as well.
Changing the hours of operation to part- time would require a change in signing and
most likely additional signage to explain the new operations of the lanes and associated
infrastructure ( e. g., direct access ramps and freeway- to- freeway connectors). If it is
decided that a change to part- time operations would also necessitate a change in the
current ingress/ egress operations, additional costs would be incurred to change the
existing striping and signing related to lane access.
4.3.9 Effectiveness Comparison With Other Freeway Management Options
t Freeway management strategies can be effective at maximizing freeway capacity,
particularly for sporadic, off- peak congestion related to incidents and special event
traffic. These strategies can be assessed as an alternative to providing the type of
benefits to general- purpose traffic than changing to part- time operations might.
A primary motivation often cited for changing from full- time to part- time HOV operation
is to make more efficient use of the roadway by providing more general- purpose
capacity during off- peak times. Some regions address this issue by assessing if other
freeway management strategies might be just as effective for a similar or lower cost.
For example, transportation officials in Washington State decided that increased
incident management and more efficient transition of the reversible express lanes was a
more effective use of funds than reverting to part- time HOV lane operations. 31
31 Seattle Post- Intelligencer, Traffic Panel Rejects the Opening up of HOV Lanes, April 21, 2001.
Orange County 37 August 1, 2002
HOV Lane Operations Study
5.0 Ingress/ Egress
This section discusses the advantages and disadvantages of limiting access and
egress to and from HOV lanes to designated locations, and separating HOV lanes from
other lanes using a buffer. All of the HOV lanes in southern California are buffer-separated,
although the width and striping of the buffer varies between facilities.
There has been very little research on the benefits and costs of buffer- separation or
limited access and egress to HOV lanes, which is surprising given the cost and
environmental impact of additional pavement width, and the substantial operating
experience of both buffer- separated and continuous access HOV facilities in North
America. The decision to provide buffers and to restrict access across the buffer is
primarily determined by regional style, preferences and perceptions.
Caltrans High Occupancy Vehicle ( HOV) Guidelines for Planning, Design, and
Operations ( July 1991) state that “ compared to contiguous HOV facilities, buffered HOV
facilities generally provide the motorists with a better level of service. This includes
higher driver comfort, extra margin of safety through providing extra maneuvering room,
and a lessening of the impact from incidents on adjoining HOV/ general- purpose lanes.”
Contiguous HOV lanes “ may be justified when right- of- way limitations preclude
separation of the HOV lane from the general- purpose traffic.”
In general, Caltrans prefers limited ingress and egress to HOV lanes when HOV lanes
are operated on a 24- hour basis, and continuous access without a buffer when HOV
lanes are operated during peak hours only32. Additionally, Caltrans HOV Guidelines
call for HOV operations to be consistent within each region of the state to promote
consistent driver expectations.
While there is currently no California state statute requiring buffer- separation or limited
ingress and egress for HOV lanes, Caltrans received direction from the provisions of SB
699, which was enacted in 1987 and required Caltrans to take steps toward
implementing a wider buffer on the SR- 55 freeway. Since that time, Caltrans has
generally incorporated a 4’ buffer into new projects in southern California, except when
right- of- way limitations preclude it. Since left- side shoulders are a higher priority than
buffers for operations and safety reasons, locations with full- width 4’ buffers also
typically include left- side shoulders. This is in contrast to portions of the system that
have been retrofitted into more constricted rights- of- way, where no buffer is provided in
places and only a minimal distance separates the HOV lane from a median barrier.
Recent investments in direct access ramps and HOV freeway- to- freeway direct
connectors aim to isolate HOV operations more completely from traffic in general-purpose
lanes, while also reducing the impact on general- purpose traffic of HOV traffic
weaving across the general- purpose lanes to enter and exit the HOV facility.
32 Antonette Clark, Caltrans Statewide HOV Lane Coordinator, ( Telephone Interview) July 24,
2002
Orange County 38 August 1, 2002
HOV Lane Operations Study
5.1 Regional Policy Variations
In North America, HOV systems are designed and operated differently to meet local
requirements and preferences. As was shown in the discussion on part- time vs. full
time HOV operation, there is no national consensus about whether and when buffer-separation
or limited ingress/ egress is required for HOV lanes.
Table 5.1 shows that 11 of the 36 cities or counties where concurrent- flow HOV lanes
are operated typically separate HOV lanes from general- purpose traffic using some
kind of a buffer. These 11 systems account for approximately 615 HOV route miles,
which is more than half of the 1,062 concurrent- flow HOV lane route- miles in North
America as of June 2001. Barrier- separated and contra- flow lanes are not included in
this total, as these facilities generally have very different operational characteristics.
Table 5.1 - Freeway HOV Systems With and Without Buffer Separation*
Buffer- separated Systems
( 614 route- miles total)
Non- buffered Systems or Routes**
( 458 route- miles total)
24 hour HOV operation,
Continuous ingress/ egress
( 91 route- miles)
¨ Seattle, WA.
¨ Vancouver, BC**
24 hour HOV operation,
Limited ingress/ egress
( 458 route- miles)
¨ Orange County
¨ Los Angeles County
¨ Riverside County
¨ San Bernardino County
¨ Denver CO.
¨ Hartford CT.
¨ Atlanta GA. ( all except I- 20)
¨ Dallas TX.
¨ Houston TX.
Part- time HOV operation
Continuous ingress/ egress
( 156 route- miles)
¨ Phoenix AZ.
¨ Atlanta GA. ( I- 20 only)
¨ Ft. Lauderdale FL.
¨ Montgomery County MD.
¨ Suffolk and Nassau Counties in NY.
¨ Northern VA.
Part- time HOV operation
Continuous ingress/ egress
( 357 route- miles)
¨ Santa Clara County***
¨ San Mateo County***
¨ Alameda County***
¨ Contra Costa County***
¨ Marin County***
¨ Sacramento
¨ San Diego County
¨ Miami, FL
¨ Orlando, FL**
¨ Honolulu, HI
¨ Boston, MA**
¨ New Jersey Turnpike**
¨ New York City**
¨ Portland, OR**
¨ Ottawa, Ontario, Canada
¨ Memphis, TN**
¨ Nashville, TN
¨ Salt Lake City, UT**
¨ Norfolk/ Virginia Beach, VA
¨ Vancouver, WA**
Notes * - Barrier- separated and contra- flow lanes excluded.
** - Single route only, not a system.
*** - San Francisco Bay Area
Orange County 39 August 1, 2002
HOV Lane Operations Study
Orange County, Los Angeles County, Riverside County and San Bernardino County
alone account for 342 route- miles, representing over half of all the buffer- separate HOV
mileage in North America. In Orange County and other Southern California counties,
motorists are restricted from crossing the buffer to enter or exit from the HOV lane, but
this is not true for all HOV systems. Five of the buffer- separated systems, accounting
for approximately one- quarter of buffer- separated HOV route miles, operate as HOV
lanes in the peak periods only. In those cases continuous access is allowed across the
buffer. Like Orange County, all systems with 24- hour HOV operations and buffer-separation
limit access and egress to designated locations only. Information examining
the experiences of locations where continuous access is permitted across a 4 foot
buffer would be desirable, although none has been published to date.
Among cities that operate HOV lanes on a 24- hour per day basis, Seattle and
Vancouver, B. C., are alone in operating HOV lanes without a buffer and with continuous
access from general- purpose lanes. Seattle uses an 8 inch continuous gore stripe to
separate the HOV lanes from other traffic, and it is legal to enter or exit from the HOV
lane at any point. In the San Francisco Bay Area and other areas with part- time HOV
lane use, a regular skip- stripe is generally used to separate HOV lanes from other traffic
to avoid driver confusion during times when the HOV lane is open to all traffic. In these
areas, signage and pavement markings such as a diamond decal are typically used to
designate the HOV lanes.
5.2 Advantages and Disadvantages
The premise behind providing buffer- separated HOV lanes and limited ingress and
egress is that it provides a higher level of service to HOV users. By separating the HOV
facility from general- purpose traffic, HOV users are expected to maintain higher speeds
when the general- purpose lanes are congested, and to feel more comfortable that
slower moving cars in general- purpose traffic congestion won’t maneuver in front of
them unexpectedly. Combined with left- side shoulders and direct access ramps and
connectors, the intent is to provide highly reliable performance to HOV users whether or
not congestion exists in adjacent lanes.
There has been little quantitative analysis of whether these results are achieved due to
the limited ingress and egress that characterizes Orange County HOV facilities, but
there is no evidence suggesting that removal of buffers or limited ingress and egress
would improve the level of service to HOV users. The most likely reason to consider
removing buffers or changing to allow continuous access would be to accommodate
part time HOV operations.
The conditions when buffer- separation and limited access and egress create
advantages and disadvantages are summarized in Table 5.2.
Orange County 40 August 1, 2002
HOV Lane Operations Study
Table 5.2: Advantages and Disadvantages of Buffer Separation With Limited
Access Versus Unlimited Access
Criterion Buffers With Limited Access Unlimited Access
Cost ¨ Buffers add cost. If right- of- way
is available, cost is lower; if
constrained or structured, costs
are higher.
¨ No incremental cost to restrict
access at project outset.
¨ Re- striping and re- signing cost
to change once open
¨ Lack of buffer reduces right- of-way
cost and impervious surface
needs.
¨ Re- striping and re- signing cost to
change once open
Safety Impacts ¨ No systematic impact on
accident rate, compared to
effect of traffic dynamics and
facility design.
¨ Concentrates merging and
weaving at designated areas,
reduces merging between
access points. Impact is
location specific.
¨ No systematic impact on
accident rate, compared to effect
of traffic dynamics and facility
design.
¨ Queued general- purpose traffic
can maneuver into HOV lane
unexpectedly, creating
perception of accident danger.
Isolation from General-
Purpose Congestion and
Incidents
¨ Minimized impact in HOV lane
from incidents and congestion
in general- purpose lanes.
¨ HOV traffic flow can be further
enhanced by combining
benefits of left- side shoulders,
direct access ramps, bus
service.
¨ HOV lane users can gain access
to all general- purpose ramps.
¨ HOV volumes can spike at
congestion hot spots as HOV
traffic shifts into the HOV lanes.
¨ HOV lane may appear
underutilized except when
freeway is congested.
Impact on General
Purpose Traffic
¨ If designed well, weaving can
be concentrated where
adequate capacity exists.
¨ Direct access further reduces
weaving to access HOV lane.
¨ Weaving is distributed along an
entire corridor
¨ Concentrated weaving at
inappropriate locations or
inadequate weave distance
exacerbates bottlenecks.
Violation Rates and
Enforceability
No significant difference is known. Requires:
¨ Adequate space for enforcement activity, and
¨ Adequate enforcement budget.
Driver Expectancy
( Regional consistency)
¨ Buffer and access treatments should be consistent with adjacent
facilities.
¨ Isolated buffer and access treatment variations may be appropriate when
a facility does not connect to other HOV facilities.
Funding/ Regulatory
Considerations
¨ SB 699 reinforces preference
for buffers in Southern
California.
Compatibility with HOV
and Transit Operation
¨ May be desired in anticipation
of future HOT lane or BRT
operation.
¨ Direct access can be provided
to further reduce bus weaving.
¨ Most appropriate when HOV
lanes are used for general-purpose
at some times.
Orange County 41 August 1, 2002
HOV Lane Operations Study
5.3 Evaluation Criteria
Some of the considerations when evaluating the merits of buffer- separation and/ or
limited ingress and egress include:
t Cost
t Safety Impacts
t Isolation from General- Purpose Congestion and Incidents
t Impact on General- Purpose Traffic
t Violation Rates and Enforceability
t Driver Expectancy ( Regional Consistency)
t Funding and Regulatory Considerations
t Compatibility with HOV and Transit Operations
t Public Perceptions
Each of these considerations is discussed below.
5.3.1 Cost
t Buffers add cost to a project initially. Once a buffer exists, changing to remove the
buffer or to provide continuous access adds re- striping and re- signing cost.
To add four feet per direction to a freeway cross- section adds cost and environmental
impacts to a project, unless the width can be made available by narrowing existing
lanes and/ or shoulders. Detailed design is required to determine the cost of providing
a buffer at a specific location. There is no incremental cost to limit access between
access points, as long as a skip- stripe separation is used to separate lanes at an at-grade
ingress/ egress point, since only a double paint stripe is needed to limit access to
the HOV lane.
To remove a buffer from a freeway, costs will be incurred for removing and replacing
existing paint stripes, and changing signage along the route. If the freeway cross-section
is below standard, then additional width can be given to substandard shoulders
and/ or lanes ( at additional re- striping cost), but if standard shoulders and lanes exist,
there is an opportunity cost to leaving four feet of pavement unused.
To retain a buffer, but to allow continuous access across it, requires removal and
replacement of the double- stripe separating lines, and replacement of signs. Typical
re- signing costs can range from $ 250 for a small barrier mounted sign to $ 3,600 for a
large overhead mounted sign panel. Typical re- striping costs can range from $ 4,000 to
$ 6,000 per- mile, depending on the type of striping and paint that is used. In locations
where lead based or toxic thermoplastic striping has previously been used, re- striping
costs can exceed $ 10,000 per- mile due to the need to use specialized equipment to
remove and capture hazardous paint particles without releasing them into the
environment.
Orange County 42 August 1, 2002
HOV Lane Operations Study
5.3.2 Safety Impacts
t Limited ingress/ egress reduces merging between ingress/ egress points. There is
no evidence that presence or absence of buffers or limited ingress and egress has
a systematic impact on safety. Traffic dynamics and design may cause buffers or
limited ingress/ egress to be an advantage in some locations and a disadvantage in
others.
There has been little systematic study of whether buffer- separated and access
restricted HOV lanes are more or less safe than continuous access HOV lanes. A
comparison of accident histories for HOV lanes in Northern and Southern California
against similar facilities without HOV lanes concluded that “ the differences in accident
experience among the freeway sections examined ( e. g., HOV vs. general- purpose
control sections) seem almost entirely related to differences in their flow and congestion
patterns rather than anything inherent in the geometric or operational characteristics of
the HOV facilities themselves.” The analysis of Los Angeles and Orange County study
sections showed that “ there are clusters of accidents at the ends of the HOV facilities
which are mainly due to geometric constraints,” but the study “ indicated no major
systematic differences in accident characteristics due to the presence of the HOV
facility.” 33
Accident rates are the result of several interactive factors, including traffic volumes, the
extent of merging and weaving and the distances cars are weaving across, and the
design of the facility including presence of shoulders and full- width lanes, sight
distance, and many other causes. Determining the independent safety impacts of an
HOV facility can be complicated if other elements are incorporated in the HOV project,
such as ramp meters, improved geometrics, or if other elements are deviated to make
room for the HOV lane. In most cases, analysis of safety impacts is site- specific.
In general, the difference between HOV lanes with continuous access versus those with
limited ingress and egress is in the distribution of accidents, rather than the accident
rate overall. With limited ingress and egress, merging and weaving is concentrated to
specific locations rather than spread throughout the length of the facility. Location of
merge areas to provide adequate weave distances and to avoid congestion hot spots is
a key factor in reducing accidents at ingress/ egress points.
On HOV lanes with continuous access from adjacent HOV lanes, cars will often move
into the HOV lane to pass, and then move back into the general- purpose lane.
Similarly, cars traveling in the HOV lane are also able to use the general- purpose lane
to pass slower moving traffic in the HOV lanes, where conditions permit. This type of
merging is eliminated in HOV lanes with limited ingress and egress. One of the
concerns HOV users face is the chance that a car stopped in the general- purpose
lanes will unexpectedly move into the HOV lane at a much lower speed in frustration
with little advance notice. Unfortunately there has been no study measuring how much
this behavior is reduced due to buffer restrictions, but HOV users are more likely to feel
they have a margin of safety due to the 4’ separation, and more so if there is a left- side
shoulder to move into to avoid a collision.
33 Sullivan ( et al), High- Occupancy Vehicle Lane Safety, September 30, 1992
Orange County 43 August 1, 2002
HOV Lane Operations Study
If HOV lanes are converted to part time operation, then analysis will be required to
determine whether a restricted buffer should be maintained. If volumes in the HOV lane
during off- peak periods would exceed the volumes that the HOV lane was designed for,
then analysis would be required of the adequacy of merging areas at the end of the
HOV facility and at ingress/ egress points to ensure that a higher volume of merging
traffic can be safely accommodated.
5.3.3 Isolation from General Purpose Congestion and Incidents
t Restricted buffers reduce the incidence of cars unexpectedly moving into the HOV
lane at lower speeds at bottleneck locations, but they do not remove all “ sympathy
slowing” at congestion and incident locations. Average speeds in Southern
California HOV lanes do not appear to be degraded when speeds are lower in
adjacent lanes, but it is hard to tell whether speed differentials are greater than in
continuous access lanes in the Bay Area or the Puget Sound region.
A key success factor for buffer- separation is the ability to maintain HOV speeds even
when incidents occur or congestion is present in the general- purpose lanes. Where
HOV lanes have unrestricted access, many HOV- eligible users will remain in general-purpose
lanes until they encounter congestion. HOV volumes jump at bottlenecks and
approaching incidents, increasing merging at those locations. When this occurs, there
is clearly an effect on HOV speeds in the area of the bottleneck, and the effect is to
cause “ friction” between the HOV lane and the adjacent general- purpose lane.
Again, limited evidence is available. Caltrans District 12 ( Orange County) Annual HOV
Report34 does not include data on speeds in HOV lanes or adjacent general- purpose
lanes. Travel time data is available from Caltrans District 7 ( Los Angeles and Ventura
Counties) HOV Annual Report35 and speed data is available from the Los Angeles
County Metropolitan Transportation Authority ( MTA) HOV Performance Program36.
These data show a substantial range of speed differentials between HOV lanes and
adjacent general- purpose lanes. Some freeways show substantial differences in peak
period speed between HOV and adjacent lanes, including I- 10 WB ( 30 mph difference)
and SR 110 NB ( 37 mph difference). Others show HOV lanes that are not significantly
higher than adjacent lanes. For example, SR 57 shows only a 2 mph difference in
speed in the HOV lanes compared to the adjacent general- purpose lanes.
The Caltrans District 4 ( San Francisco Bay Area) HOV Report37 also shows a range of
speed differentials, with most Bay Area HOV lanes maintaining a 65 MPH speed
34 Caltrans District 12, 2001 District 12 Annual HOV Report, California Department of
Transportation, District 12 Orange County, HOV and Toll Roads Branch, May 2002.
35 Caltrans District 7, 2001 HOV Annual Report, California Department of Transportation, District
7 Los Angeles and Ventura County, May 2002.
36 Parsons Brinckerhoff Quade and Douglas, ( et al), HOV Performance Program Technical
Memoranda # 3- 6, 8- 10 & 14- 17 HOV Data Collection, Compilation and Analysis, Los Angeles
County Metropolitan Transportation Authority, March 22, 2002.
37 Caltrans District 4, 2001 District 4 HOV Report, California Department of Transportation,
District 4 Oakland, Office of Highway Operations, February 2002.
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regardless of traffic in general purpose lanes, but a few cases where HOV speeds are
degraded when significant general- purpose congestion is present.
Part- time versus full- time HOV operation in Northern and Southern California make
direct comparisons difficult. The Puget Sound ( Seattle) area also allows continuous
access to HOV lanes, but operates HOV lanes on a 24- hour basis. The Puget Sound
HOV Annual Report38 does not report a peak period speed, but reports a similar range
of minutes saved per mile in HOV lanes as those shown in the MTA HOV Performance
Program for Los Angeles County. The TRAC report includes graphs showing the
percentage of days that speeds in HOV lanes are greater than 45 mph over the course
of a day at specific locations. These graphs show that speeds deteriorate in HOV lanes
as a result of congestion in general purpose lanes, but the effect varies by location.
As Puget Sound traffic congestion has worsened and expanded into the midday
periods, buffer- separation has been discussed for the first time during planning studies
for I- 405 and SR- 520, especially since there is some desire not to preclude options to
implement bus rapid transit ( BRT) service or multiple- lane High- Occupancy Toll ( HOT)
lane options in the future.
Transit operators using HOV lanes in the Puget Sound area are instructed not to exceed
15 mph greater than the speed of adjacent general- purpose lanes, and empirical
evidence suggests that friction between HOV and adjacent traffic lanes is negatively
impacting the performance of HOV lanes there. Whether or not a restricted buffer
reduces the friction between lanes, transit operating policies can limit the speed
differential for continuous access facilities even if design or traffic dynamics do not.
To fully understand the systematic safety and operations impact of limiting HOV lane
access, a significant evaluation effort is needed. Such an evaluation would need to
isolate the contribution of HOV demand, buffer separation and limited ingress/ egress,
and focus on traffic dynamics at bottleneck and incident locations to determine the
effect of HOV volumes, violations, and merging and weaving impacts at those locations,
since aggregate statistics from long HOV lane segments are not conclusive.
5.3.4 Impact on General- Purpose Traffic
t There is no data to suggest that the presence or absence of buffer- separation or
limited ingress/ egress has a systematic impact on general- purpose traffic. Traffic
dynamics and design may cause buffers or limited ingress/ egress to be an
advantage in some locations and a disadvantage in others.
The discussion under “ safety” also applies here. If ingress/ egress points are located in
places where weaving distances are too short, or in congestion hot spots, then weaving
conflicts will be created that will exacerbate general- purpose traffic congestion.
Conversely, a restricted buffer can be used to control a weaving problem in places
where weaving would create a traffic problem.
38 Washington State Transportation Center ( TRAC), HOV Lane Performance Monitoring: 2000
Report, Washington State Department of Transportation, February 2002.
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5.3.5 Violation Rates and Enforceability
t The combination of 2+ occupancy, full- time operation and limited ingress and
egress results in very low HOV violation rates, but it is not possible to isolate the
contribution of limited ingress and egress to this result. Limited ingress/ egress
makes it inherently more difficult to leave the HOV lane when violating the minimum
occupancy requirement in order to avoid detection, with violating the buffer
crossing prohibition.
Several factors influence violation rates, and it is often difficult to distinguish which
factors are at play. Significant differences in HOV violation rates are shown when
comparing the violation rates for Southern and Northern California freeways as shown in
Table 2- 4. Much of the difference might be explained by differing HOV occupancy
requirements, or by the use of part- time HOV lane operations. I- 10 in Los Angeles
County is operated at 3+ during peak periods and shows a significantly higher violation
rate than other Southern California HOV facilities, although this inconsistency with other
Southern California facilities may be attributable to driver confusion resulting from the
recent implementation of the part- time minimum occupancy variations. Considerably
higher violation rates in Northern California are more likely related to part- time operation
and limited enforcement during the “ shoulders” of the peak period. Therefore, it is
difficult to separate out the contribution to violation rates that are the result of buffer-separation
and limited ingress/ egress.
According to the California Highway Patrol, buffer separate facilities are typically safer
for officers to enforce because there is more space for officers to get out of traffic when
they make a stop. Furthermore, the CHP indicates that once a violator is spotted, it is
easier to pursue them in a buffer separated facility because they are confined to the
lane until the next egress point unless they chose to cross the buffer, which also
constitutes a violation. In a continuous access facility, a violator would more easily be
able to elude detection by moving into the general- purpose lane when an officer is
sighted39. By providing limited ingress and egress locations, it is possible that violators
will be less likely to move into HOV lanes with a restricted buffer, because it will be
more difficult to leave the lane to avoid being detected, since crossing the buffer is
easier to detect and is an equal offense to violating occupancy requirements.
5.3.6 Driver Expectancy / Regional Consistency
t Removing limited ingress and egress would need to occur on all buffer- separated
facilities in Southern California to meet this criterion.
Most of the freeway HOV facilities in Southern California have become interconnected
into a network of HOV lanes and connectors. From a driver’s point of view, rules and
operation of the highway system should not be appreciable different from one freeway
facility to another; not only for customer convenience, but also to reduce driver
confusion and related safety concerns.
39 Sgt. Lori Hardy, California Highway Patrol, Headquarters, Sacramento, ( Telephone Interview)
August 7, 2002.
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SR- 14 remains separate and independent from other HOV facilities, and it is less
congested over a 24- hour basis, so a more reasonable case can be made to continue
to operate it differently from other HOV facilities as a demonstration project in the short
term. By contrast, HOV facilities in Orange County are connected to or continue into
other counties, and it would be very difficult to remove limited access and egress on
routes in Orange County unless the same change was adopted in other adjacent
counties.
Caltrans HOV Guidelines recommend that the design features and operational
characteristics of HOV facilities “ should also be uniform and consistent within a region.”
This criterion will carry a higher weight than site- specific criteria such as safety and
isolation from general- purpose lane congestion, unless a systematic impact to these
criteria can be identified. When making regional policy, it has to be assumed that good
design decisions will be made that avoid site- specific issues that may be encountered.
However, before any change can be made, a thorough operational and safety
assessment would be needed to determine whether there are fatal flaws, or design
revisions that would be needed for safe operation.
5.3.7 Funding and Regulatory Considerations
t Route 55 was required by legislation to include a 4’ buffer, but no funding or
regulatory constraints limit conversion of HOV lanes to allow continuous access.
SB 699 amended the California Vehicle Code in 1987 to require a 4’ buffer to be
provided on SR- 55, and Caltrans has complied with the legislative intent by providing
buffers as a standard feature where practicable. There are no Federal or California
regulations requiring limited ingress and egress, or buffer separation other than on SR-
55. As shown in Table 5.1, some regions allow traffic to cross a buffer, although
these are all cases where HOV lanes are operated on a part- time basis.
5.3.8 Compatibility with ( Current and Future) HOV and Transit Operations
t A decision to operate Orange County HOV lanes on a part- time basis would make
continuous access more favorable, but not a requirement. If future use of HOV
lanes for BRT or HOT lane operation is desired, then retaining a buffer and limited
ingress/ egress helps to preserve those options.
The strongest argument for changing Orange County HOV lanes to provide continuous
access would be consistency with a change to part- time HOV operation. However,
experience in Orange County indicates traffic conditions are most suited to the
provision of full- time HOV lane operations. In Northern California, Caltrans has chosen
to design part- time HOV lanes to appear as general purpose lanes to avoid driver
confusion during times when HOV restrictions are not in force. But there are a variety of
options available. For example, HOV lanes could be operated as express lanes or HOT
lanes rather than as general purpose lanes, allowing non- HOV’s to enter and exit at
certain times of day. Alternatively, buffers could be maintained, but access allowed
across the buffer, if detailed analysis does not uncover operational and/ or safety flaws.
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6.0 Decision Making Framework
Orange County has a history of being proactive in involving key agency stakeholders in
decisions related to HOV lane project development and operation policies. The agency
relationships between OCTA and Caltrans, CHP and FHWA, in particular, have served
Orange County well. A high degree of investment effectiveness has resulted. As
evidence, Orange County’s carpool lane system:
t Has the highest level of HOV use of any HOV system in the world,
t Moves more vehicles each day than the Los Angeles or Bay Area HOV lane
systems,
t Provides more direct access ramps and freeway- to- freeway direct connections
than any system,
t Has one of the highest motorist compliance rates with an extremely low number
of violations,
t Achieves one of the highest levels of “ utility” moving more people than an
adjacent general use lane, even for many mid- day hours, and
t Based on a wide cross section of users and non- users from recent surveys in
Los Angeles County, probably has a very high public satisfaction rating.
However, every HOV system needs periodic reassessment of its operation policies.
OCTA and Caltrans have performed similar assessments in the past.
A framework for assessing and changing HOV rules and regulations involves a number
of agency stakeholders. These include state and locally elected officials, Caltrans,
CHP, SCAG, Southern California Air Quality Management District, various federal
agencies and adjoining transportation authorities in Riverside, San Diego, Los Angeles
and San Bernardino Counties. Each are vested with specific authorities and has a
potential stake in HOV policy outcomes. Listed below are some of the identified issues
that would probably need to be addressed.
6.1 Caltrans
Caltrans is a co- sponsoring agency with OCTA, vested with specific design approval,
operations and maintenance authority over HOV lanes. Caltrans’ primary objectives are
the safe and efficient operation of the state’s roadway system. Safety is a particular
issue that would be raised with respect to the relatively high volumes of HOV traffic
currently using HOV lanes, high volumes of merging traffic observed on system
connectors, and ramifications associated with changing policies that could result in
changes to facility design.
Only one exception has been granted by Caltrans for part- time operation of HOV lanes
in Southern California. SR- 14 in Los Angeles County received demonstration status due
primarily to the low level of HOV demand evidenced in the off- peak period. The LAO
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report on this demonstration project and Caltrans both agree that growing demand in
the future will necessitate a return to full- time operations. Such a justification would not
exist for Orange County’s HOV lanes, based on current levels of utilization. Caltrans
approval would be needed at Caltrans District 12, Caltrans Headquarters HOV Branch,
and Caltrans Traffic Operations for either a change in hours of operation or change in
ingress/ egress designation. Additionally, legislation would need to be introduced and
approved to modify the California Vehicle Code and other relevant state statutes.
6.2 California Highway Patrol ( CHP)
The CHP, Santa Ana Division, has supported the current HOV lane operation policies
for Orange County. Their role in enforcing the HOV lanes would be made more
complicated by part- time operation, and the level of staffing may need to be increased
to sustain a low percentage of violations, particularly in the fringe periods when the
HOV lanes transition from HOV- only to general- purpose use. CHP would need to be
involved in a decision changing HOV lane operating hours.
6.3 Southern California Association of Governments ( SCAG)
SCAG provides coordination of long range transportation planning and funding for six
Southern California counties, as well as modeling air quality impacts associated with
transportation improvements. Changing HOV lanes to part- time operation would, in
particular, influence the level of daily HOV use and its attendant impacts on air quality.
These assumptions would need to be accounted for in future air quality modeling for
Orange County and surrounding counties, since impacts from this operational change
will likely influence HOV use for the region.
6.4 Southern California Air Quality Management District ( AQMD)
HOV lanes are considered a mitigation measure for transportation related air quality
impacts. In Southern California, air quality conformity is monitored by AQMD. Changes
to HOV operating hours will need to be approved by AQMD to determine if further
mitigation will be needed. A lower number of HOV trips due to loss of mid- day
incentive could result in other measures needing to be taken to offset air quality
impacts.
6.5 Adjoining Transportation Authorities
The development of the region’s HOV lane system has involved a wide variety of
funding mechanisms by state, federal and county sources. Variations in HOV operation
policies between Orange County and other counties could jeopardize funds for
developing or extending these regional HOV projects. Financial and operational
impacts could vary between one county and another, and specific impacts will need to
be ascertained and accepted by the adjoining counties impacted.
6.6 Federal Highway Administration ( FHWA)
FHWA has specific guidelines related to making significant operational changes to HOV
facilities. A summary of the FHWA Program Guidance for HOV Lanes is included in
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Appendix B. Making a change to part- time operation would represent, in this
particular instance, a measurable impact due to the large number of direct access
ramps connecting HOV lanes to other freeways and local streets. The removal of
designated ingress and egress would also represent a significant impact for these
same reasons.
Safe traffic operation is one of the most critical objectives supported by FHWA. Federal
guidelines for controlled access roadways require safe weaving distances between left
side HOV access and right side general use access ramps to local streets and
freeways. Specific designs approved with each Orange County freeway project would
be voided by the indiscriminate opening of HOV lane access locations, or by opening
median oriented direct access ramps to general- purpose traffic that could induce
erratic weaving from other general- purpose lanes. Based on recent precedent in
federal policy guidance forwarded to Washington State regarding the Puget Sound
HOV system, FHWA will likely require that all left side direct access ramps be closed or
gated to prohibit use to general- purpose traffic during the periods when they are not in
use by HOV traffic. There are a large number of high volume direct access ramps in
Orange County that are potentially impacted by this issue. FHWA approval of these
operation changes is required, or federal funding for past and future projects will be at
risk.
The closing of direct access ramps and freeway- to- freeway connectors would be
exacerbated by the lack of alternative ingress/ egress locations and inconsistent
signage for HOV ingress/ egress locations. In order to fulfill any FHWA requirement to
close or gate left side access ramps, alternative ingress/ egress locations and variable
replacement signage would be necessary.
6.7 Data and Resource Needs
Changing HOV operation policy requires an investment in performance monitoring,
review of operation data, agency involvement and legislation to move forward.
Changing rules also has a cost implication associated with the needed changes in
signing and pavement markings. A wide array of agencies will have involvement and in
some cases, approval responsibilities over, an HOV operation policy change.
The team developing this report identified the above list based on current experience.
This is by no means an exhaustive list of all likely requirements associated with a facility
specific or systemwide HOV policy change. Further investigation with each resource
agency would be needed to ascertain their specific requirements and issues they
would raise that need to be satisfied, and site- specific operation and safety issues
would need to be identified and analyzed. Likely data needs for a more detailed
analysis before moving forward would include the following:
t Daily and hourly vehicle and person moving data for HOV and general
purpose lanes,
t Speed data for HOV and general- purpose lanes,
t Accident statistics,
t Enforcement data related to violations and citations issued,
t Air quality data,
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t Project designs, deviations, access reports, and environmental
documents,
t Direct access locations,
t Signing and striping costs associated with the operational changes,
t Public opinion research,
t Legislative review ( state and federal), and
t FHWA information needs for approval process.
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7.0 Conclusions
The HOV system in Orange County is currently one of the most extensive, effective and
productive HOV systems anywhere. During the peak hours, the HOV system in Orange
County carries the highest average vehicle volumes of any HOV system reflecting the
benefits of this extensive and continuous network of HOV facilities. During weekdays
from 6: 00 AM to 8: 00 PM, and on weekends from 10: 00 AM to 7: 00 PM, the HOV lanes
in Orange County typically sustain volumes in excess of Caltrans minimum peak hour
HOV lane volume guideline of 800 vph. Orange County HOV lanes consistently move
as many or more people in fewer vehicles than the adjacent general- purpose lanes,
fulfilling a fundamental goal of HOV facilities and reflecting the effectiveness and
productivity of the system. The Orange County HOV system stands as an example of
the benefits of investing in a comprehensive and continuous HOV system as an element
of the transportation infrastructure.
The duration of the peak periods on Orange County and Southern California freeways is
longer than that experienced in Northern California, and is the most immediate reason
for the differences in regional HOV operational policy. The combined influences of the
duration of congestion, the level of congestion, the comparatively high HOV lane traffic
volumes throughout the day and the relatively balanced directional peak traffic flows in
Orange County and adjoining counties was the initial rationale for designating full- time
HOV lane operations in this region. These traffic conditions have become more
pronounced in Southern California during the time the Orange County HOV system has
evolved, further justifying the current policy for full- time lane operations.
A change in operational policy on the Orange County HOV system has a significant
impact on the operation of HOV systems in adjoining counties, and vice versa.
Changing one route or county system could confuse motorists, particularly where
systems connect to other regional freeways. This confusion has potential legal
implications, likelihood for higher violations, higher incidents and more difficultly in HOV
lane enforcement.
Changing HOV policy in Orange County would also have institutional implications.
Caltrans HOV Guidelines state that the design features and operational characteristics
of any HOV system should be “ uniform and consistent within a region.” Any change in
Orange County HOV operating policy would require the approval of Caltrans and
coordination with other regional agencies. Furthermore, any change in operation policy
would most likely constitute a “ significant operational change” according to the Federal
Highway Administration, prompting a requirement for federal review and approval.
Each option for HOV lane hours of operation and access location has inherent
advantages and disadvantages. Many of these issues have been discussed in the
report, particularly as they relate to the current operational policies in Orange County.
The following tables provide a summary of the advantages and disadvantages of
changing the current HOV lane operational policies in Orange County. Table 7.1
describes the advantages and disadvantages of changing from full- time to part- time
HOV lane operations. Table 7.2 summarizes the advantages and disadvantages of
removing the current designated access restrictions.
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Table 7.1 – Advantages and Disadvantages of Changing from Full- Time to Part- Time HOV Lane
Operation
Criteria Advantages Disadvantages
Cost ¨ Requires replacement signs and pavement re- striping to
remove buffers ( assuming buffers and designated
access operations are removed to better facilitate part-time
operations).
¨ Requires gates on local direct access ramps or added
cost for removal.
¨ Requires additional CHP enforcement during fringe
periods.
Safety
Impacts
¨ Potential for improved
general- purpose level of
service during mid- day.
¨ Creates potential for motorist confusion, especially
where HOV lanes continue in adjoining counties.
Potential for more accidents at these transitions.
¨ If designated access is continued along with general-purpose
use of lane, higher volumes weaving at
ingress/ egress locations would increase accident
potential.
Impact on
HOV
Operation
¨ None during peak periods
of greatest demand and
use.
¨ No HOV incentives in off- peak periods resulting in lower
daily level of HOV use.
¨ Greater potential for congestion because peak
spreading will be reversed to concentrate HOVs in peak
periods.
Impact on
Enforcement
¨ May reduce HOV- related
enforcement costs due to
the reduction in
enforcement time needed.
¨ Potential confusion on the part of motorists may
contribute to higher violations ( particularly near the
beginning or end of the part- time operation, or at the
county line if adjacent counties are operating full- time)
¨ Increased difficulty of enforcement.
Impact on
General
Purpose
Traffic
¨ More potential for all traffic
to use HOV lanes in off- peak
period.
¨ No incentive for general- purpose traffic to use HOV
lanes in the off- peak period unless existing general-purpose
lanes are congested.
Regional
Impacts
¨ Potential to be more
compatible with HOV lane
operation policies in other
parts of the state
¨ Inconsistent with Los Angeles, San Bernardino and
Riverside County HOV lanes. Either other counties have
to revise their operating rules or lane transitions will need
to be added to allow other traffic to escape/ enter HOV
lane
¨ Added off- peak direction capacity will create queueing
where general- purpose lane drops occur when leaving
Orange County
Direct Access
Impacts
¨ More potential general-purpose
use of freeway- to-freeway
connectors
¨ Local access direct connectors will need to be gated for
HOVs only during peak periods or closed and removed.
Ingress/
Egress
Operations
¨ Inconclusive. Likely options include re- striping and eliminating the limited ingress/ egress
HOV policy, or keeping the designated access and operating the lanes as general- purpose
traffic express lanes during non- HOV designated times. Both options have significant
implications.
Air Quality
Impacts
¨ Unknown. Probably neutral. Greater general- purpose level of service gain in off- peak
periods is likely to be offset by loss of HOV incentives and reduced HOV use during these
periods.
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Table 7.2 – Advantages and Disadvantages of Removing Designated Access Locations
Criteria Advantages Disadvantages
Cost ¨ Requires re- striping and re- signing HOV lanes.
¨ May increase the number of required
enforcement areas.
Safety Impacts ¨ May improve accident rates at
current access site locations, due to
current concentration of merging
and weaving.
¨ Accident rates for HOV routes will not likely
change over current, but will be spread more
uniformly along HOV routes.
¨ Ability to use access restrictions in locations
where lane geometry or sight distances create
hazardous conditions for weaving will be
eliminated.
Impact on
HOV
Operation
¨ Greater flexibility to enter and exit
HOV lanes.
¨ Greater potential for queuing and weaving
closer to freeway interchanges where direct
access connections are not provided, resulting
in potential lower level of service for all lanes
Impact on
General
Purpose
Traffic
¨ Safer when HOV lanes are used
part- time because HOV lanes look
like general- purpose lanes
Regional
Impacts
¨ More consistent with projects
elsewhere in the state.
¨ Inconsistent with Los Angeles, San Bernardino
and Riverside County HOV lanes.
Direct Access
Impacts
¨ Access restrictions will still be needed in
vicinity of direct access ramps to prohibit
erratic weaving.
¨ HOV ramps will not be able to be used by
general- purpose traffic
Air Quality
Impacts
¨ Unknown. Probably neutral. Changing access has little impact on levels of service for either
user group.
Should the Orange County Transportation Authority wish to pursue changes in the HOV
hours of operations and/ or ingress/ egress restrictions, there are several combinations
of part- time operation and limited ingress/ egress that could be implemented, and each
" package" has a different set