T R A F F I C
O P E R A T I O N S
S T R A T E G I E S
! Background
! Current Status
! Opportunities for
Implementation
April 2000
TOPS
Executive Summary
Traffic Operations Strategies ( TOPS) 1
Executive Summary
In appropriating State Highway Account funds for
Fiscal Year 1999- 2000 Caltrans Operations ( Item
2660- 001- 0042), the Legislature included supple-mental
budget language that required the
Department of Transportation to submit a report on
Traffic Operations Strategies ( TOPS). This report
responds to the Legislative requirement by describ-ing
the motivation for TOPS, the cur-rent
status of TOPS, and opportuni-ties
for implementing TOPS projects.
Some aspects of the legislative
request, including the use of mov-able
barriers and the interrelation-ship
between transportation plan-ning
and rapid urban development
on congested corridors, will be
addressed in future submittals.
INTRODUCTION
We currently face a major transportation challenge in
California. Congestion has grown significantly on our
highways despite efforts to expand our infrastructure
to meet increasing demand. Looking ahead,
California’s population is forecasted to grow over 30
percent in the next 20 years. Our recent experience
tells us that congestion will increase even faster than
population: since 1990, our overall congestion has
increased more than 50 percent while our population
has grown by a little more than ten percent. 1
This rapid increase in congestion can be explained by
complicated traffic flow interactions. In general terms,
as demand ( i. e., number of vehicles) exceeds capacity
( i. e., maximum number of vehicles that a given high-way
can serve), traffic choke points are created and our
customers experience congestion. As congestion wors-ens,
the traffic flow rate on our highways is reduced. At
speeds of 45 miles per hour or more, each lane on a
typical urban highway can carry around 2,000 vehicles
per hour. When congestion occurs and speeds fall
below 35 miles per hour, the flow rate per lane can
drop considerably. Under congested conditions, a flow
rate of only 1,500 vehicles per hour is typical. 2
We refer to congestion that results from demand regu-larly
exceeding capacity as recurrent congestion. Urban
commuters face this problem almost every weekday on
our busiest highways.
An equally important type of congestion, sometimes even
more frustrating to our customers, results from accidents,
special events, weather conditions, and
other unusual circumstances. We refer
to this as non- recurrent congestion.
These unusual circumstances often lead
to choke points ( e. g., at an accident
location), which in turn reduce the traf-fic
volume ( or flow rate) carried by our
system.
Any comprehensive strategy to address
congestion must address both types of
congestion. Moreover, the strategy must
aim to reduce overall demand to the extent feasible and
practical, and then manage the transportation system in a
manner that restores under- utilized capacity.
This strategy has been emerging since the realiza-tion
in the 70s that fiscal and environmental con-straints
would restrict the 50s- 60s era “ build- build-build”
option as a solution to transportation prob-lems.
Originally known as transportation system
management, the strategy embodies the philoso-phy
of planning, programming, developing, and
operating the system, be it the overall transporta-tion
system or a significant component such as the
highway system, so that the efficiency and effec-tiveness
of the system is maximized. This is clearly
stated in Caltrans’ strategic goals as “ Optimize the
System.” The TOPS version of system management
will be an aggressive effort to utilize efficiently the
existing infrastructure that lies at the heart of sys-tem
management. A two- pronged TOPS approach of
influencing demand and tapping all available
capacity, is quintessential system management. The
proposed TOPS projects’ operational and perfor-mance
focus acts as a bridge between major system
1 1998 California Department of Transportation Congestion Monitoring Report ( HICOMP)
2 Transportation Research Board, Highway Capacity Manual, Special Report 209, Third Edition, 1998
The goals of
TOPS are to reduce
congestion, increase
trip reliability, and
enhance safety
management, transportation demand management
and system expansion efforts.
WHAT IS TOPS?
TOPS is a strategy for addressing congestion problems
through better system management. The goals of
TOPS are to reduce congestion, increase trip pre-dictability,
and enhance safety, especially on our most
congested corridors. Initially, the focus of TOPS will be
on the state highway system for which we plan to:
• Leverage today’s enhanced communication technol-ogy
to equip our state freeways fully with intelli-gence
that provides real- time information, which in
turn will help us partner with the public and with
the private sector to better manage our transporta-tion
system, and
• Adjust our current infrastructure to maximize traffic
flows and restore under- utilized capacity corridor-and
system- wide.
TOPS must ultimately address all modes, incorporate
local streets and arterials, and address the demand side
of transportation in a comprehensive manner.
In essence, TOPS offers an “ Operations First” approach
to corridor and system management. By evaluating the
demands and constraints for each transportation cor-ridor
and understanding the inter- relationships among
corridors, we can better manage capacity and reduce
congestion.
However, TOPS should not be viewed as a replace-ment
for system expansion. For certain corridors, sys-tem
expansion is and will remain the only reasonable
solution. TOPS investments and system expansion
should be viewed as complementary.
TOPS implementation can be divided into four ele-ments
as follows:
• Complete the “ intelligence” component of our existing
infrastructure to improve traffic flow management
• Address infrastructure limitations with physical
operational improvements at the corridor and sys-tem
levels to alleviate choke points, increase overall
traffic flows and restore all under- utilized capacities
• Fill all operational gaps in the high occupancy vehi-cle
( HOV) network to eliminate traffic disruptions
that result when HOVs merge with other vehicles
• Modify selected freeway- to- freeway interchanges
to minimize traffic flow disruptions and resulting
congestion.
CURRENT STATUS
Over the last ten years, we have made significant
progress in the development and deployment of tools
to manage and operate the transportation system bet-ter.
Since the full deployment of these tools has relied
on emerging technologies, they could not be part of a
comprehensive strategy until now. Such a strategy is
possible due to the rapid advancement of communi-cations
technology and Caltrans- sponsored research
initiatives. However, to implement TOPS, we need
more funding, coordination with regional and local
agencies, and integration with other modes. The status
of the four highway- related TOPS elements can be
summarized as follows:
• Intelligent Infrastructure – We estimate that
approximately 20 percent of the intelligent infra-structure
planned under TOPS has been implement-ed
under previous efforts. Caltrans has programmed
an additional 15 percent of the necessary intelligent
infrastructure.
• Physical Operational Improvements – These
improvements address bottlenecks or choke points
created by demand exceeding capacity, primarily at
on- and off- ramps.
• HOV Network Gaps – California operates approxi-mately
925 miles of HOV lanes. Nearly 127 addition-al
HOV lane- miles are under construction, and 792
more HOV lane- miles are proposed.
• Freeway Interchange Modifications – We have
identified a number of freeway interchanges where
modifications will improve flow significantly.
WHERE DO WE GO FROM HERE?
Caltrans has already begun to develop comprehensive
plans to implement TOPS. Every Caltrans district has
submitted preliminary project lists, which will be
refined over the next few months to produce a
detailed 10- Year TOPS Plan. The 10- Year Plan will be
completed over the coming year and presented to the
Legislature no later than January, 2001.
Executive Summary
2 Traffic Operations Strategies ( TOPS)
However, even as these plans are finalized, we antici-pate
implementing significant portions of the
Intelligent Infrastructure and Physical Operational
Improvements TOPS elements. Implementation will
include corridor- wide demonstration projects for
each district.
TOPS implementation will require institutional coor-dination
in planning, operations, and funding. Regional
planning is currently accomplished through the local
regional transportation planning process and the
Regional Transportation Improvement Program
( RTIP). Caltrans districts are and will continue to work
with local and regional planning agencies to ensure
that projects identified in the 10- Year TOPS Plan are
embedded in the regional planning process and at
least partly financed through RTIPs. The Department
will also work with these agencies to coordinate high-way-
related activities with other modal priorities, and
to develop comprehensive regional system manage-ment
plans in the coming year.
TOPS FUNDING OPPORTUNITIES
Caltrans anticipates that initial ( first- level) projects
will focus on intelligent infrastructure and physical
operational improvements. Other investments will
focus on other aspects of TOPS.
Executive Summary
Traffic Operations Strategies ( TOPS) 3
Representative TOPS Projects
LEVEL 1 LEVEL 2 LEVEL 3
Intelligent
Infrastructure
• Changeable Message
Signs
• Closed- Circuit Televisions
• Communication Links
• Fiber Optics
• Highway Advisory
Radios
• Metering and Metering
Control
• Roadway Weather
Information System
• Signal Upgrades
• Traffic Monitoring
Stations
• Transportation
Management Center
Upgrades
Physical Operational
Improvements
• Alignment Upgrades
• Auxiliary Lanes
• Intersection Upgrades
• Lane/ Shoulder Widening
• Passing Lanes
• Ramp Modifications
• Other
HOV Network Gaps
• HOV Connectors
• HOV Drop Ramps
• HOV/ Managed Lanes
• Other
Freeway Interchange
Modifications
• Freeway Connectors
• Freeway Connector
Metering
Some TOPS investments may be funded through the
State Highway Operation and Protection Program
( SHOPP).
This year may present a unique, although short- lived,
funding opportunity for TOPS. The California
Transportation Commission ( CTC) identified a poten-tial
lapse in federal funding due to project delivery,
primarily in the Local Assistance Program. The CTC
created a “ Contingency Fund” to prevent such a lapse
and directed that this fund emphasize TOPS as part of
the SHOPP.
Not all contingency funds may be available for TOPS.
SHOPP funding plus Congestion Mitigation and Air
Quality Improvement ( CMAQ) Contingency Funds can
support a portion of the first- level TOPS investments
required over the next ten years. Regional Share of
Surface Transportation Program ( RSTP) Contingency
Funds increase available funding.
However, Caltrans cannot count on the availability of
the Contingency Fund. Funding for the needs identi-fied
as first- level TOPS investments must come from a
variety of sources, such as local funding commitments
and future years of the State Transportation
Improvement Program ( STIP), SHOPP, or resource
sharing by the private sector. Several regions have
expressed interest and in some cases committed fund-ing
to these projects through the Regional
Transportation Improvement Program ( RTIP). Caltrans
will continue to work closely with the regions and the
private sector to obtain complete funding for TOPS.
HOW EFFECTIVE WILL TOPS BE?
Initial estimates demonstrate that TOPS projects are
cost- effective investments that provide greater returns
than do typical system expansion projects. The aver-age
system expansion project in the 1998 Inter-
Regional Transportation Improvement Plan ( ITIP) pro-duced
a benefit- cost ratio of only 2.4 to 1.
The benefits of TOPS include the reductions of: delay,
user costs, accidents, and air pollution. These categories
of benefits are conservatively estimated and summa-rized
in the exhibit below for first- level TOPS invest-ments.
The total benefit/ cost ratio for the first level of TOPS
investments is more than triple that of the average
roadway expansion project. Moreover, this ratio does
not reflect the additional benefits that will accrue
from increased productivity, synergies among types of
projects, or the further stimulation of the communica-tion
industry in California. In all, Caltrans strongly
believes in the merits of TOPS and will work closely
with its partners to implement it.
Executive Summary
4 Traffic Operations Strategies ( TOPS)
Summary of TOPS Benefits
Category Benefit- Cost Ratio
Level 1: Intelligent Infrastructure 10.1 to 1
Level 1: Physical Operational Improvements 8.3 to 1
Level 1: TOTAL 8.9 to 1
Level 2: HOV Network Gaps TBD
Level 3: Freeway Interchange Modifications TBD
1. Background
Traffic Operations Strategies ( TOPS) 5
In appropriating State Highway Account funds for
Fiscal Year 1999- 2000 Caltrans Operations ( Item
2660- 001- 0042), the Legislature included supple-mental
budget language that required the
Department of Transportation to submit a report on
Traffic Operations Strategies ( TOPS). This report
responds to the Legislative require-ment
by describing the motivation
for TOPS, the current status of TOPS,
and opportunities for implementing
TOPS projects. Some aspects of the
legislative request, including the use
of movable barriers and the interre-lationship
between transportation
planning and rapid urban develop-ment
on congested corridors, will be
addressed in future submittals.
1.1 INTRODUCTION
We currently face a major transportation challenge in
California. Congestion has grown significantly on
California highways despite our efforts to meet increas-ing
demand by building new highways and expanding
existing ones as well as providing new and expanded
transit services. Looking ahead, California’s population
is forecasted to grow by over 30 percent in the next 20
years. This population increase is the equivalent of
adding another San Diego and San Francisco Bay Area to
the state, and our recent experience tells us that con-gestion
will increase even faster than population.
Consider the following historical trends:
• Between 1990 and 1998, California’s population
grew by a little more than ten percent. During that
same time period, congestion, as reported in the
1998 HICOMP report, grew by more than 50 per-cent
statewide. The growth in congestion outpaced
population growth by a factor of five.
• Congestion in rapidly developing urban areas ( e. g.,
Riverside, San Bernandino, Sacramento) grew even
faster than the State average. Congestion in our Los
Angeles- based District 7 grew slower during the
same period. In total though, Los Angeles com-muters
still experience the most delay in the State.
• During that same period, the State has invested bil-lions
to expand the freeway system, develop new
and expand existing rail systems, and develop the
core of a high occupancy vehicle ( HOV) sub- system
in major metropolitan areas ( e. g. Los Angeles,
Orange County, and the San Francisco Bay Area).
Clearly, our ability to expand our
physical infrastructure cannot
address the increasing demand for
transportation. California is not alone
in facing a problem with congestion.
The Texas Transportation Institute’s
1998 Annual Urban Mobility Study
indicates that mobility has worsened
for travelers in most of the 68 cities
studied nationally, no matter how
mobility is measured. Road construc-tion
has historically played a major
role in helping us hold the line against increasing con-gestion.
As the Texas Transportation Institute acknowl-edges
in its study, “ it is very difficult to maintain the
financial and public support to add roads and lanes as
fast as traffic volume grows.” A new approach is nec-essary
for tackling highway congestion.
Over the last 10 years, Caltrans and its regional part-ners
have recognized that capacity increases can no
longer be considered the only solution to congestion.
This realization, combined with the maintenance and
management responsibilities imposed by an increas-ingly
complex transportation system, have necessitat-ed
a change in Caltrans’ role to emphasize system
management.
1.2 THE NATURE OF CONGESTION
This rapid increase in congestion can be explained by
complicated traffic flow interactions. In general terms,
as demand ( i. e., number of vehicles) exceeds capacity
( i. e., maximum number of vehicles that a given high-way
can serve), traffic choke points are created and
our customers experience congestion. As congestion
worsens, the traffic flow rate on our highways is
reduced. At speeds of 45 miles per hour or more, each
lane on a typical urban highway can carry around
1. Background
It is very difficult
to maintain financial
and public support
to add roads and
lanes as fast as traffic
volume grows
2,000 vehicles per hour. When congestion occurs and
speeds fall below 35 miles per hour, the flow rate per
lane can drop considerably. A flow rate of only 1,500
vehicles per hour is typical at speeds between 20 and
30 miles per hour. 3
We refer to this type of congestion, where demand
exceeds capacity on a regular basis as recurrent
congestion. Urban commuters face this problem
almost every weekday on our busiest highways.
An equally important type of conges-tion,
sometimes even more frustrat-ing
to our customers, results from
accidents, special events, weather
conditions, and other unusual cir-cumstances.
We refer to this as non-recurrent
congestion. These unusual
circumstances often lead to choke
points ( e. g., at an accident location),
which in turn reduce the traffic vol-ume
( or flow rate) carried by our sys-tem.
Caltrans conducted an analysis
in Southern California and estimated
that non- recurrent and recurrent congestion cause
roughly equal delays for our customers. Non- recur-rent
congestion is also the primary factor for travel
time “ unpredictability,” since customers cannot plan
for it.
Any comprehensive strategy to address congestion
must improve mobility ( i. e., reduce delay), improve
predictability ( i. e., minimize the impacts of incidents
and other unusual conditions), and enhance the safety
of our customers. To achieve these goals, such a strat-egy
must address both recurrent and non- recurrent
congestion. It can do so by addressing both the
demand for travel and the capacity of our transporta-tion
system. It must balance the total demand among
modes ( e. g., highway, transit, and HOV) and it must
take advantage of the under- utilized capacity of our
highway system.
Today, the need to “ manage” the State’s transporta-tion
system is as critical as the need to expand and
maintain it. Fiscal and environmental limits on high-way
expansion have highlighted the need for com-prehensive
system management. In recent years,
Caltrans districts have added components such as
ramp metering, High Occupancy Vehicle ( HOV)
lanes and transportation management centers to
traditional lane and roadway expansion projects.
These components have been implemented primar-ily
to address specific problem areas. However, they
also provide the necessary foundation for larger-scale
system management.
We believe that TOPS leverages
this foundation, offering compre-hensive
system management that
initially addresses the highway sys-tem.
However, to truly optimize
our entire transportation system,
the highway strategies must be
fully integrated with other modes
and must incorporate local streets
and arterials. As such, successful
coordination with regional and
local transportation agencies will
be a critical success factor for reaping the full ben-efits
of our strategy.
1.3 REPORT FORMAT
The remainder of this report is organized as follows:
• Section 2 defines TOPS, identifies its primary cate-gories,
and discusses the reasoning behind this
emerging transportation strategy.
• Section 3 summarizes the current status of TOPS and
preliminary plans for implementing TOPS through-out
California.
• Section 4 discusses funding opportunities for imple-menting
projects under the TOPS framework.
• Section 5 summarizes the benefits of representative
investments from TOPS and how these benefits
address corridor and system congestion.
• Section 6 presents our conclusions related to TOPS
and the need to commit to its implementation.
1. Background
6 Traffic Operations Strategies ( TOPS)
Today, the need
to “ manage” the
State’s transportation
system is as critical
as the need to expand
and maintain it
3 Transportation Research Board, Highway Capacity Manual, Special Report 209, Third Edition, 1998
2. What is TOPS?
Traffic Operations Strategies ( TOPS) 7
TOPS is a comprehensive strategy to reduce conges-tion
through improved system management. The goals
of TOPS are to reduce congestion, especially on our
most congested corridors, improve the predictability
of travel time, and enhance the safety of our trans-portation
system. Initially, the focus of TOPS is on the
state highway system for which we plan to:
• Leverage today’s enhanced communication technol-ogy
to equip our state highway system fully with
intelligence that provides real time information,
allowing us to partner with the public to manage
our transportation system better, and
• Adjust our current infrastructure to maximize traffic
flows and restore under- utilized capacity.
However, TOPS must ultimately address all modes,
incorporate local streets and arterials, and work hand-in-
hand with infrastructure expansion strategies. As
such, it requires coordination with regional and local
agencies, and partnerships with the customer to
address the demand side of transportation. Pricing
policies, land use coordination and modal connectivi-ty
all must be addressed through a coordination effort
illustrated in Exhibit 2- 1 below.
When fully implemented and deployed, TOPS invest-ments
may provide congestion relief equivalent to
adding as much as one lane to many congested
freeway segments in California's urban areas. Since
the cost of implementing TOPS is a fraction of the
cost of the equivalent infrastructure expansion,
TOPS is a more cost- effective investment.
Exhibit 2- 1: TOPS Coordination
2. What is TOPS?
The overall benefit- cost ratio of TOPS is expected to be
about nine- to- one ( 9: 1) compared to less than three- to-one
( 3: 1) for the typical system expansion project.
TOPS shifts our focus to corridor and system manage-ment,
but TOPS should not be viewed as a replacement
for infrastructure expansion. Adding roads and lanes
has proven useful in addressing mobility needs in the
past and cannot be ignored for the future. For certain
corridors in California, system expansion is and will
remain the only reasonable solution. TOPS investments
and system expansion should work in concert, ulti-mately
managing the total transportation system.
TOPS offers an “ Operations First” approach to corridor
and system planning. By evaluating the demands and
constraints for each transportation corridor, we can
manage capacity without focusing entirely on tradi-tional
system expansion. TOPS is designed to increase
mobility and improve system performance.
By emphasizing statewide congestion management,
TOPS provides a platform for inter- district planning
and minimizes gaps or inconsistencies in regional and
statewide system management efforts. Coordination
between districts will ensure that issues affecting con-tiguous
districts are not “ dropped” at the district
boundary, ultimately providing motorists with seam-less
traffic congestion measures and integrated
sources of timely, accurate traffic information. District
TOPS plans will be integrated and coordinated at the
State level, with particular attention to neighboring
districts in congested urban areas.
2.1 ELEMENTS OF TOPS
TOPS focuses our planning, implementation, and
operations on system management. This approach
complements current and projected infrastructure
expansion investments and focuses future efforts in
four primary areas:
• Completing the “ intelligence” component of
our existing infrastructure. New communica-tions
technology, better monitoring tools, and
new control equipment can create an “ intelligent
infrastructure” that allows optimal routing of
travelers to their desired destinations. Sample
investments include system- wide adaptive ramp
metering, changeable message signs, traffic man-agement
centers, incident response systems,
advanced traveler information systems, and real-time
performance measurement. These improve-ments
provide the capacity for accurate, focused
performance measurement, resulting in the real-time
feedback necessary to maximize the perfor-mance
of the existing system.
• Correcting infrastructure limitations at the
corridor and system levels with physical
improvements to alleviate bottlenecks and
increase overall traffic flow. Potential invest-ments
include the construction of freeway auxiliary
lanes ( merge lanes provided before and after on-ramps),
the modification of ramp/ city street access,
and the addition of short passing lanes and truck
climbing lanes. As a result of a corridor approach to
planning, projects in this category will allow
motorists to take advantage of previously underuti-lized
capacity. Since these projects are smaller in
scale, they can typically be implemented faster than
larger infrastructure expansion projects.
• Filling gaps in the high occupancy vehicle
( HOV) network to eliminate traffic disrup-tions
that result when HOVs merge with other
vehicles. Merging causes traffic delays that can be
experienced miles away. Potential investments to
address this problem include the construction of
drop ramps and freeway- to- freeway HOV connec-tors,
as well as closing HOV gaps that exist within
corridors. Because these investments improve trav-el
times for HOVs corridor- wide, they can be
expected to encourage an overall increase in car-pooling.
In addition, HOV network improvements
facilitate the implementation of rapid bus systems.
• Modifying selected freeway- to- freeway inter-changes
to minimize traffic flow disruptions
and resulting congestion. These modifications
generally include the re- routing of merging traffic
beyond the intersection point and through extend-ed
auxiliary lanes. Although generally more expen-sive,
projects in this category can be extremely
effective for improving traffic flows at major urban
freeway interchanges. Freeway- to- freeway inter-changes
with design deficiencies can create signifi-cant
choke points because they require traffic to
merge or weave. Improvements at these inter-changes
will reduce recurrent delays.
Caltrans has developed TOPS implementation plans
that combined projects in each of these categories on
a corridor and system basis. The current status of TOPS
and a summary of these plans are described in the
next section.
2. What is TOPS?
8 Traffic Operations Strategies ( TOPS)
3. Current Status of TOPS
Traffic Operations Strategies ( TOPS) 9
California has made an enormous investment in its
state highway system, which is estimated at $ 300 bil-lion
( in today’s dollars) over the last century. Within
the last two decades, the State has recognized the
growing need to manage and operate the system bet-ter.
Some progress has been made in the development
and deployment of components, such as ramp meters,
that give us the tools to help manage and operate the
transportation system.
Since these tools have relied on emerging technolo-gies,
they could not be part of a comprehensive strat-egy
until now. Moreover, research sponsored by
Caltrans has provided us with critical tools for plan-ning
and analysis. Even though many of these tools
have been funded with limited budgets to address site-specific
problems, TOPS can build on the foundation
created by our existing infrastructure by incorporat-ing
four main components. The status of each compo-nent
is summarized as follows:
• Intelligent Infrastructure – Caltrans has deployed
intelligent infrastructure elements over the last two
decades. TOPS requires additional investment in
these components. In addition, recent innovations
enable us to plan and implement a more fully inte-grated
intelligent infrastructure linked by new
telecommunications technologies. Exhibit 3- 1 pro-vides
an example of how telecommunications can
link field sensors, ramp meters, and transportation
management centers.
We estimate that approximately 20 percent of the intel-ligent
infrastructure planned under TOPS has been
implemented under previous efforts. In addition, we
estimate that an additional 15 percent has been pro-grammed.
Table 3- 1 summarizes the status of this cate-gory
by sub- element.
3. Current Status of TOPS
Exhibit 3- 1: Example of Integrated Intelligent Infrastructure
Linked field
sensors, ramp
meters and
TMCs facilitate
better system
management.
• Physical Operational Improvements – These
improvements address bottlenecks or choke points
that are created by existing capacity limitations.
Caltrans has historically addressed these limitations
on a project- by- project basis in a fiscally constrained
environment as part of the SHOPP program. Caltrans
districts have identified the projects necessary to
address these deficiencies on a statewide basis.
Specific needs are described further in Section 4 of
this report. Exhibit 3- 2 illustrates a typical physical
operational improvement project.
Table 3- 1: Intelligent Infrastructure Buildout
* Existing TMCs in Districts 3, 4, 6, 7, 8, 10, 11, and 12
** Interim or final TMCs in Districts 3, 7, and 12, and upgrade to TMC in District 6
*** New TMCs in Districts 6 and 8, improvements to TMC in Districts 7 and 11, and final TMC in District 8
3. Current Status of TOPS
10 Traffic Operations Strategies ( TOPS)
EXISTING PROGRAMMED UNFUNDED TOTAL
ELEMENTS UNITS UNITS UNITS UNITS
Transportation
Management Centers
( TMCs) 8* 4** 5*** 11
Closed Circuit
Televisions 570 623 920 2113
Fixed Changeable
Message Signs 357 125 460 942
Fixed Highway
Advisory Radio 72 46 135 253
Metering and Metering
Control 1786 234 1512 3532
Traffic Monitoring
Stations 2997 874 3475 7076
Roadway Weather
Information Systems 27 16 198 126
Fiber Optics
Communications ( Miles) 152.5 553.9 1317 2023
• HOV Gap Closures – Over the last 10 years,
Caltrans and its regional partners have taken the
first steps towards constructing a full HOV network
by implementing HOV lane additions on a corridor
basis. Today, California operates approximately 925
miles of HOV lanes. Nearly 127 additional HOV lane-miles
are under construction, and 792 more HOV
lane- miles are proposed. TOPS plans aim to link
existing and future HOV lanes, filling any gaps to
create a fully connected HOV network. These pro-jects
will include drop ramps and other strategies to
alleviate the need for HOVs to cross other lanes of
traffic. In addition, these projects will benefit future
bus rapid transit systems. Exhibits 3- 3 and 3- 4 pro-vide
illustrations of HOV drop ramp and connector
projects.
3. Current Status of TOPS
Traffic Operations Strategies ( TOPS) 11
Exhibit 3- 2: Auxiliary Lane and Ramp Modifications
Disruptions due
to merging traffic
are reduced
Exhibit 3- 3: HOV Drop Ramp
Disruptions due
to exiting HOVs
are reduced.
• Freeway Interchange Modifications – Increasing
demand has put significant pressure on major urban
freeway interchanges. In some cases, the original
design for these interchanges has become an imped-iment
to traffic flows. We have identified a number
of freeway interchanges where modifications will
improve flow significantly. Exhibit 3- 5 provides an
illustrative example of a freeway interchange modifi-cation.
Exhibit 3- 5: Freeway Interchange Modification
Modified
connectors
provide more
room for traffic
to merge safely.
3. Current Status of TOPS
12 Traffic Operations Strategies ( TOPS)
Exhibit 3- 4: HOV Connector
HOVs can switch
freeways without
cutting across
lanes.
Our approach to integrating these components and
implementing TOPS focuses on corridor and system-wide
mobility problems. Exhibit 3- 6 illustrates how a
regional transportation system can be divided into
corridors in the San Francisco Bay Area. These desig-nations
build on the ones used by the Metropolitan
Transportation Commission ( MTC) in its 1998
Regional Transportation Plan. The same type of desig-nation
has been or will be made shortly for every
district in California. Once the corridors are defined,
Exhibit 3- 6: San Francisco Bay Area Transportation Corridors
3. Current Status of TOPS
Traffic Operations Strategies ( TOPS) 13
we overlay the known choke points for each corridor
and analyze each separately and in conjunction with
other corridors in the region. This analysis has already
started in many districts and will continue for some
time leading to corridor- wide implementation strate-gies.
These projects can be staged as described in the
sections that follow.
3.1 WHERE DO WE GO FROM HERE?
We already have a tremendous foundation for imple-menting
TOPS. In today’s dollars, the State has invest-ed
about $ 300 billion in the existing state highway sys-tem.
It has served us remarkably well given that over
75 percent was built more than twenty years ago. In
addition, the State has incrementally added compo-nents
of the intelligent infrastructure envisioned
under TOPS. A significant portion of the required intel-ligent
infrastructure is either installed or programmed.
The State now has an opportunity to take advantage of
its previous investments to implement TOPS rapidly as a
cost- effective strategy for addressing California’s conges-tion.
Full implementation requires progress in two pri-mary
areas:
• Developing state and regionally focused TOPS imple-mentation
plans
• Assuring appropriate TOPS funding.
In the short term, each district will select one of its
corridors for demonstration deployment. Investments
required for the demonstrations will be given higher
funding priority. Other corridors will continue to be
analyzed and prioritized for subsequent deployment.
3.2 TOPS IMPLEMENTATION PLANS
Caltrans has already begun to develop comprehensive
plans for implementing TOPS. Every Caltrans district
has submitted preliminary project lists, which will be
refined over the next few months to produce a
detailed 10- Year TOPS Plan. The 10- Year Plan will be
completed over the coming year and presented to the
Legislature no later than this time next year.
Highway congestion is not confined to urban areas,
therefore projects are proposed for every district in the
state. As illustrated in Table 3- 2, TOPS projects can be bro-ken
into three potential investment levels:
3. Current Status of TOPS
14 Traffic Operations Strategies ( TOPS)
Table 3- 2: Representative TOPS Projects
LEVEL 1 LEVEL 2 LEVEL 3
Intelligent
Infrastructure
• Changeable Message
Signs
• Closed- Circuit Televisions
• Communication Links
• Fiber Optics
• Highway Advisory
Radios
• Metering and Metering
Control
• Roadway Weather
Information System
• Signal Upgrades
• Traffic Monitoring
Stations
• Transportation
Management Center
Upgrades
Physical Operational
Improvements
• Alignment Upgrades
• Auxiliary Lanes
• Intersection Upgrades
• Lane/ Shoulder Widening
• Passing Lanes
• Ramp Modifications
• Other
HOV Network Gaps
• HOV Connectors
• HOV Drop Ramps
• HOV/ Managed Lanes
• Other
Freeway Interchange
Modifications
• Freeway Connectors
• Freeway Connector
Metering
• Level 1 focuses on congestion at choke points through
minor operational improvements, such as auxiliary
lanes and intersection modifications, and the addi-tion/
coordination of intelligent infrastructure. This level
can be further separated into operational improve-ments
and investments in intelligent infrastructure.
• Level 2 adds HOV capacity
and operational improvements.
Representative projects include
HOV gap closures, moveable barri-er
projects, HOV drop ramps, and
HOV ramp meter bypasses.
• Level 3 includes major operational
improvements, such as freeway- to-freeway
connectors.
Caltrans anticipates that initial
investments will be focused on the
first level. By addressing choke
points along specific corridors and
completing the intelligent infrastructure required to
produce congestion- reducing benefits beyond what
the physical infrastructure alone can produce, the first
level of TOPS investment adds significantly to the
state’s ability to manage traffic congestion. As Exhibit
3- 7 illustrates, combined operational improvements
and infrastructure investments for the first level rep-resent
over 45 percent of TOPS projects.
3.3 REGIONAL COORDINATION
TOPS represents a system operation- centered
approach that requires institutional coordination at
the planning, operations and funding levels. Full imple-mentation
of these strategies will require significant
regional coordination.
Currently, regional planning is accom-plished
through the local regional
transportation planning process
and the development of the
Regional Transportation Improve-ment
Program ( RTIP).
Caltrans districts are working and will
continue to work with local and
regional planning agencies to pro-duce
comprehensive TOPS plans.
These plans will ensure that the pro-jects
identified in the 10- Year TOPS
Plan are embedded in the regional plans and the
regional planning process and are at least partly
financed through RTIPs.
Conversely, Caltrans will coordinate with regional
agencies in developing the State SHOPP plan to
demonstrate the commitment to overall system man-agement
and develop effective partnerships to com-bat
congestion.
3. Current Status of TOPS
Traffic Operations Strategies ( TOPS) 15
Exhibit 3- 7: Potential Split of TOPS Projects by Level
Level 1: Intelligent Infrastructure
Level 1: Physical Operational Improvement
Level 2: HOV Network Gaps
Level 3: Freeway Interchange Modifications
TOPS represents
an operation- centered
approach that requires
institutional coordination
at the planning,
operations, and funding
levels
Some TOPS investments are likely to be funded through
the State Highway Operation and Protection Program
( SHOPP). The Ten- Year State Highway System
Rehabilitation Plan is the guiding document that sets
SHOPP strategies and objectives, describes system defi-ciencies,
and recommends funding. SHOPP funding
extends to four elements: traffic safety, roadway rehabil-itation,
roadside rehabilitation, and operations.
This year may present a unique, although short- lived,
funding opportunity for TOPS. At its August 1999
meeting, the California Transportation Commission
( CTC) adopted the four- year 2000 State Transportation
Improvement Program ( STIP) Fund Estimate. During
deliberations, the CTC identified a potential lapse in
federal funding in the Local Assistance Program. The
CTC created a “ Contingency Fund” to prevent such a
lapse. The CTC directed that this fund would empha-size
TOPS and that the Department would manage the
fund with the SHOPP.
Three federal programs were identified for the
Contingency Fund:
• Congestion Mitigation and Air Quality Improvement
( CMAQ)
• Regional Share of Surface Transportation Program
( RSTP)
• Regional Share of Bridge Program ( BR).
However, not all contingency funds may be available
for TOPS. The federal programs identified have condi-tions
limiting the types of projects, geographic areas,
and timing for fund usage.
The Ten- Year SHOPP Plan targets CMAQ funding for
TOPS projects. RSTP funds may be appropriate for
TOPS. The 10- Year SHOPP Plan currently directs
these funds toward expediting safety projects, pave-ment
rehabilitation projects, and protective better-ments.
Caltrans cannot count on the Contingency Fund
being available in this or any future years. The
unfunded needs identified for first- level TOPS pro-jects
may need to come from other sources, such as
local funding commitments and future years of the
STIP. Getting local funding commitments requires
coordination with local and regional entities. The
investments proposed in TOPS are consistent with
needs identified by the California Alliance for
Advanced Transportation Systems ( CAATS) ITS
Deployment Initiatives Strategic Plan, which has
been developed with significant local and regional
involvement.
4. TOPS Funding Opportunities
4. TOPS Funding Opportunities
16 Traffic Operations Strategies ( TOPS)
5. Summary of TOPS Benefits
TOPS focuses on system management and therefore
yields system- wide impacts. It achieves larger benefits
than can be achieved by individual projects such as
the placement of a Changeable Message Sign ( CMS) or
the construction of an auxiliary lane. For example,
communications systems, ramp meters, and ramp
widening constructed at a key bottleneck, such as
Interstate 210 near Mountain Street in Los Angeles, and
coordinated in operation with other TOPS improve-ments
are likely to produce greater benefits due to
network effects than any of these investments made
individually.
Additional benefits result when investments to
address congestion along specific corridors and at
particular bottlenecks are coordinat-ed
so that the entire network of high-ways
is placed in balance. This coor-dination
extends beyond project
placement to include construction
and operations issues. TOPS’ empha-sis
on corridor and system- wide
impacts will include a consideration
of the timing of construction pro-jects
in order to minimize delay and
will provide an intelligent infrastruc-ture
that supports synchronized
operations.
5.1 HOW EFFECTIVE WILL TOPS BE?
Caltrans estimates that TOPS will produce significant
benefits for relatively small costs compared to typical
STIP projects. To estimate these benefits, Caltrans
worked with researchers at the University of California
at Berkeley and Irvine. 4 The types of benefits we
expect from the full implementation of TOPS include:
• Mobility – We expect a total reduction in delay due
to congestion as we balance demand across our sys-tems
and recapture under- utilized capacities on the
state highway system. We also expect delay reduc-tion
due to improved incident detection and man-agement
activities. Although not included in our
benefit calculations, the aggregate delay reductions
will have a positive impact on productivity, which in
turn helps the economy.
• Safety – We expect improvements in all aspects of
incident management. As a result, we anticipate an
overall reduction in secondary accidents that occur
at incident locations. As we reduce congestion, we
will also reduce the total number of accidents.
• Reliability/ Predictability – As we reduce the total
number of accidents and the time it takes to
respond to and clear accidents, we expect trip time
predictability to improve significantly.
• Environment – Vehicles emit
higher rates of pollution during
stop and go traffic than at higher
speeds. We have estimated the ben-efits
that result from air pollution
emission reductions. This benefit is
especially relevant in non- attain-ment
regions such as Los Angeles.
• Vehicle Operating Costs – As
stop and go traffic is reduced, vehi-cle
operating costs are also reduced
due to lower fuel consumption and
decreased vehicle wear.
We added all the benefits, with the exception of safe-ty
and reliability, which are difficult to quantify or pre-dict,
and divided the sum by the cost to derive the
aggregate benefit/ cost ratio. As a result, we estimate
that the first level of TOPS will produce a benefit- cost
ratio of 8.9 to 1, far higher than the typical STIP pro-ject.
For comparison purposes, consider the returns of
recent transportation projects in California. The
Department initially analyzed 145 projects for consid-eration
in the Inter- Regional Transportation
Improvement Plan ( ITIP) portion of the 1998 State
5. Summary of TOPS Benefits
We estimate that the
first level of TOPS
will produce a benefit-cost
ratio of 8.9 to 1,
far higher than the
typical STIP project
4 The University of California at Irvine ( UCI) modeled the effect of intelligent infrastructure investments on non- recurrent con-gestion
and the benefits of physical operational improvements for representative sections of Orange County. The University of
California at Berkeley ( UCB) tested the effect of intelligent infrastructure investments on recurrent congestion for a sample net-work
using the FHWA ITS Deployment Analysis System ( IDAS).
Traffic Operations Strategies ( TOPS) 17
Transportation Improvement Plan ( STIP). These pro-jects
accounted for a total statewide investment of
$ 5.1 billion with an average benefit- cost ratio of 2.7 to
1. System expansion projects, such as lane additions,
freeway conversions and bypasses, produced benefit-cost
ratios of only 2.4 to 1.
Based on the modeling conducted by UCI and UCB,
Table 5- 1 shows the potential benefits of TOPS, if we
assume that similar benefit- cost ratios resulted
statewide.
The benefits associated with implementing Level 1
TOPS are discussed in more detail below. Benefits can
be broken down by whether they result from intelli-gent
infrastructure or physical operational improve-ments.
The intelligent infrastructure will help us
address both recurrent and non- recurrent congestion
and provide two sets of benefits. Physical improve-ments
will target recurrent congestion only and pro-vide
a single set of benefits.
5.2 INTELLIGENT INFRASTRUCTURE AND
RECURRENT CONGESTION
Recurrent congestion describes the regular, everyday
rush- hour delays that occur when highway design
capacities are exceeded, while non- recurrent conges-tion
is caused by irregularly occurring events. These
delays are a major problem on today’s freeways. The
last Highway Congestion Monitoring Program
( HICOMP) report indicates that nearly 418,100 daily
vehicle- hours of delay due to recurrent congestion
occurred statewide in 1998. Since HICOMP monitors
congestion only on urban freeway segments with a
history of recurrent congestion and excludes conges-tion
on other State highways and in rural areas, total
recurrent congestion on all California highways is like-ly
to be higher.
From the public’s perspective, the most noticeable
effect of recurrent congestion is increased delays and
reduced mobility at major and minor bottlenecks,
such as the I- 580/ I- 880/ I- 80/ SR24 interchange ( fre-quently
called “ the Maze”) in the San Francisco Bay
Area. Intelligent infrastructure holds the potential for
reducing recurrent congestion through metering and
traffic monitoring. Metering programs, such as the
timing lights at the San Francisco Bay Bridge toll plaza
and ramp meters in Southern California, have been
shown to reduce travel time delay significantly. To get
a sense of the benefits of these metering programs,
consider the traffic snarls that result on the rare days
when the timing lights are not operational at the Bay
Bridge toll plaza. Traffic monitoring allows metering
to be coordinated and optimized across the highway
system.
UCB examined the potential effects of coordinating a
network of ramp meters using an intelligent central-ized
control system. Simulations using the federally-sponsored
IDAS program showed that adding central-ized
control to metering systems reduces total travel
time by an additional 13.1 percent compared to ramp
meters alone. If a travel time reduction similar to that
forecasted by UCB were to occur in Orange County,
the intelligent infrastructure would produce a benefit-cost
return of 5.7 to 1. Since these projects also have
the potential to reduce non- recurrent congestion, they
may produce even further benefits.
5. Summary of TOPS Benefits
18 Traffic Operations Strategies ( TOPS)
Table 5- 1: Summary of TOPS Benefits
Category Benefit- Cost Ratio
Level 1: Intelligent Infrastructure 10.1 to 1
Level 1: Physical Operational Improvements 8.3 to 1
Level 1: TOTAL 8.9 to 1
Level 2: HOV Network Gaps TBD
Level 3: Freeway Interchange Modifications TBD
5.3 INTELLIGENT INFRASTRUCTURE AND
NON- RECURRENT CONGESTION
Intelligent infrastructure, such as ramp metering con-trol
or advanced traveler information systems, also has
the potential to reduce non- recurrent congestion. The
most difficult problem associated with non- recurrent
congestion is that it can be unpredictable, since it is
caused by irregularly occurring events, such as acci-dents,
weather, special events, maintenance, and con-struction.
Research conducted by Caltrans indicates
that total delays due to non- recurrent congestion are
roughly equal to total recurrent delays. Since the loca-tion,
duration, and magnitude of the congestion can-not
be predicted, these delays cannot be “ fixed”
through physical improvements.
TOPS addresses non- recurrent congestion by applying
advanced technologies in traveler information and
operational controls. Monitoring systems, such as loop
detectors and weather information systems, sense the
occurrence of congestion- producing events. Traveler
information systems, such as changeable message
signs and highway advisory radios, warn travelers of
congestion ahead and offer alternate routes.
Operational controls, such as ramp and freeway
meters, ensure that additional traffic does not con-tribute
to the congestion. Emerging technologies, such
as global positioning systems ( GPS) and on- board
computers, can provide additional tools for combating
congestion. ( These technologies also offer opportuni-ties
for public- private partnerships. TOPS initiatives
will be coordinated with CAATS to ensure that these
opportunities can be fully realized.)
To illustrate the benefits of TOPS on non- recurrent
congestion, the University of California at Irvine ( UCI)
modeled the impact of centralized ramp meter control
and coordinated traveler information systems in the
area of the Orange County Y formed by Interstate 5,
Interstate 405 and State Route 133.
UCI found that, across a variety of scenarios, com-bined
advanced traveler information systems ( ATIS)
and advanced traffic management systems ( ATMS)
reduce non- recurrent delay by 33 percent. Assuming
that our existing traffic management centers ( TMCs)
already achieve a quarter of these benefits and that
similar benefits would occur throughout Orange
County, this reduction in delay translates into benefit-cost
ratio of 4.4 to 1. When added to the benefits asso-ciated
with the reduction in recurrent delay, this intel-ligent
infrastructure investment produces a total
return of 10.1 to 1.
5.4 PHYSICAL OPERATIONAL
IMPROVEMENTS
Level 1 TOPS projects coordinate intelligent infra-structure
with projects to address bottlenecks or
choke points that are created by unanticipated design
deficiencies. To measure the impact of implementing
projects that address design deficiencies, the
University of California at Irvine ( UCI) simulated the
impact of implementing twelve projects that address
choke points throughout Orange County.
Each project addresses a specific roadway bottleneck
through a combination of improvements. For instance,
I- 405 between Talbert Avenue and Beach Boulevard
experiences severe congestion and long delays due to
weaving traffic and highway design deficiencies. The
proposed solution to this problem is to extend auxiliary
lanes and reconstruct the interchange at Brookhurst.
UCI found that the twelve projects reduced travel
times in Orange County by 14 percent on average.
This translates to an overall benefit- cost ratio of 8.3 to
1. Benefit- cost ratios for individual projects ranged
from 4 to 1 to more than 60 to 1.
5. Summary of TOPS Benefits
Traffic Operations Strategies ( TOPS) 19
The research, analysis, and evaluation of TOPS pro-jects
clearly indicate that it is a strategy that must be
implemented aggressively. This is especially true for
level- one projects ( i. e., intelligent infrastructure and
physical operational improvements), for which we
conducted in- depth testing and evaluation. The 9: 1
benefit- cost ratio of these invest-ments
is almost three times as large
as traditional highway expansion
projects. Moreover, these same
investments will increase the bene-fits
associated with expansion pro-jects
by maximizing the utilization of
any added physical capacity.
California is not alone in recognizing
the need for and the benefits derived
from operation- centric strategies. In
Europe, the Netherlands implement-ed
most of its intelligent infrastructure projects,
including an automatic and operator controlled traffic
management ( MTM) system and reports that:
• Overall travel time decreased by 10 to 15
percent.
• Accident frequency declined by as much as 20 per-cent.
• The number of vehicles involved in accidents was
reduced by 30 percent. 5
Although our own estimates are more conservative,
clearly we all want to achieve such benefits and more.
As we move towards implementing TOPS, we must
also stress the need to manage the demand side of
transportation. TOPS will buy us some time and will
optimize our highway system and ultimately help opti-mize
our entire multi- modal, multi-jurisdictional
system. However, even
an optimized system can and will be
overwhelmed when demand contin-ues
to exceed capacity by a large
margin.
Over the next few years, expect
Caltrans to implement aggressively
all the TOPS projects for which fund-ing
has been secured. Also expect us
to work with the private sector to
exploit fully opportunities to inte-grate
communication networks and encourage spin-off
product development. In the end, full system man-agement
must involve the private sector as well as the
individual traveler.
6. Conclusion
20 Traffic Operations Strategies ( TOPS)
6. Conclusion
5 ITS Annual Review 1999, authored by Pernilla Hogman, Cap Gemini, Sweden
Over the next few
years, expect Caltrans
to implement
aggressively all the
TOPS projects for which
funding has been
secured
Gray Davis
Governor
Maria Contreras- Sweet
Secretary, Business, Transport and Housing Agency
Jeff Morales
Director, California Department of Transportation
Kim Nystrom
Program Manager, Traffic Operations
For additional copies of this report,
please contact Stacy Watson at ( 916) 654- 6097 or by email:
Stacy_ Watson@ dot. ca. gov.
Gray Davis
Governor
Maria Contreras- Sweet
Secretary, Business, Transport and Housing Agency
Jeff Morales
Director, California Department of Transportation
Kim Nystrom
Program Manager, Traffic Operations
For additional copies of this report,
please contact Stacy Watson at ( 916) 654- 6097 or by email:
Stacy_ Watson@ dot. ca. gov.