May 2010
Reprint Report: UCPRC- RP- 2010- 03
Hiigghhwaayy Nooiissee Abbaatteemeenntt::
Pllaannnniinngg Toooollss aanndd Daanniisshh Exxaampplleess
Author:
Hans Bendtsen, Danish Road Institute— Road Directorate
This report is based on research performed by the Danish Road Institute- Road Directorate
on behalf of the University of California Pavement Research Center for the California
Department of Transportation, and is reprinted here in its original form.
Work Conducted as Part of the “ Supplementary Studies for Caltrans QPR Program” Contract
PREPARED FOR:
California Department of Transportation
( Caltrans)
Division of Research and Innovation
PREPARED BY:
The Danish Road Institute—
Road Directorate and
University of California
Pavement Research Center
Danish Road Institute
ii UCPRC- RP- 2010- 03
DOCUMENT RETRIEVAL PAGE Reprint Report
UCPRC- RP- 2010- 03
Title: Highway Noise Abatement: Planning Tools and Danish Examples
Author: Hans Bendtsen
Prepared for:
Caltrans
FHWA No.:
CA101735C
Date Work Submitted:
July 2009
Date:
May 2010
Contract/ Subcontract Nos.:
Caltrans Contract: 65A0293
UC DRI- DK: Subcontract 08- 001779- 01
Status:
Final
Version No:
1
Abstract:
This report presents a series of methods implemented in Denmark and other European countries for the assessment
and control of the impacts of highway noise on the neighboring public. It introduces Danish guidelines for the
assessment of noise impact. Also described are examples of noise abatement planning for three different cases: planning
of new highways, planning of highway widening projects, and noise abatement on existing highways. Experience shows
that there is no single approach that can remove all noise problems along highways. It will be necessary for more
effective noise abatement to take different approaches together, including noise- reducing pavements, noise barriers,
facade insulation, and proper land use strategies. Harmonized public- private partnership is also critical for successful
implementation of public policy and regulations related to noise abatement.
Keywords: Highway noise, Noise abatement, Noise- reducing pavements, noise barriers, facade insulation
Proposals for implementation: No recommendations
Related documents:
• H. Bendtsen, H., Q. Lu, and E. Kohler. 2009. Temperature Influence on Road Traffic Noise: Californian OBSI
Measurement Study. Reprint Report: UCPRC- RP- 2009- 02
• Bendtsen, H. 2009. Noise Barrier Design: Danish and Some European Examples. Reprint Report: UCPRC- RP-
2010- 04
• H. Bendtsen, H., Q. Lu, and E. Kohler. 2009. Acoustic Aging of Asphalt Pavements: A Californian/ Danish
Comparison. Reprint Report: UCPRC- RP- 2010- 01
Signatures:
Hans Bendtsen
1st Author
DRI- DK
John T. Harvey
Technical Review
UCPRC
John T. Harvey
Principal Investigator
UCPRC
S. David Lim
Contract Manager
Caltrans
UCPRC- RR- 2010- 03 iii
DISCLAIMER
This report is based on a subcontract research study performed by the Danish Road Institute- Road Directorate
( DRI- DK) on behalf of the University of California Pavement Research Center ( UCPRC) for the California
Department of Transportation ( Caltrans). The contents of this report reflect the views of the authors and DRI-DK
who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily
reflect the official views or policies of the UCPRC, the State of California or the Federal Highway
Administration. This report does not constitute a standard, specification, or regulation. The content of the
original is unchanged in this version and has been reprinted with the consent of DRI- DK.
For more information:
University of California Pavement Research Center, Davis
One Shields Avenue, Davis, CA 95616
University of California Pavement Research Center, Berkeley
1353 S. 46th St., Bldg. 452, Richmond, CA 94804
www. ucprc. ucdavis. edu
Danish Road Institute
Report 173
2009
Hans Bendtsen
Highway noise
abatement
Planning tools and Danish examples
xx
3
Contents
Executive summary ....................................................................................................... 5
Sammenfatning.............................................................................................................. 7
Preface .......................................................................................................................... 9
Forord ........................................................................................................................ 10
1. Introduction ............................................................................................................. 11
1.1 Methods for noise abatement ............................................................................ 11
1.2 Organisation of noise abatement ....................................................................... 12
1.3 Structure of the report ....................................................................................... 15
2. Good governance in noise abatement ...................................................................... 17
3. Guidelines, prediction and evaluation ..................................................................... 19
3.1 Noise guidelines ................................................................................................ 19
3.2 Noise prediction ................................................................................................ 20
3.3 The Noise Exposure Factor ............................................................................... 22
3.4 Socio- economic assessment of noise ................................................................ 25
4. Planning of new highways....................................................................................... 27
4.1 An example ....................................................................................................... 27
4.2 General measures of noise abatement ............................................................... 30
5. Planning of widening existing highways................................................................. 33
5.1 Environmental Impact Assessment ................................................................... 34
5.2 Evaluation of noise reducing pavements........................................................... 36
6. Noise abatement on existing highways.................................................................... 39
6.1 Façade insulation............................................................................................... 39
6.2 Noise action plan............................................................................................... 41
6.3 System for tendering noise reducing pavements............................................... 43
6.4 Other measures of noise abatement................................................................... 45
7. New housing along exiting highways...................................................................... 49
8. References ............................................................................................................... 53
4
5
Executive summary
When constructing new buildings or roads in Denmark, special consideration is given
to traffic noise. A new national noise map indicates that around 30 % of Danish
homes are exposed to noise levels that exceed the threshold value of 58 dB ( LDEN) and
that noise problems are concentrated in cities. This report presents a series of methods
and strategies for noise abatement. There is no single method that can remove all noise
problems along highways and in cities. It will be necessary to address the noise
abatement on several different levels:
• At the source: this covers vehicles, tire, pavements, traffic and speed.
• Along the propagation path: in the form of noise barriers etc.
• At the receiver: in the form of façade insulation and local barriers.
The background for the report is experiences and ideas from the Danish Road Direc-torate
as well as from other European countries. As an introduction, fourteen recom-mendations
to National Road Administrations for good governance regarding noise
management and abatement are presented.
In Denmark dwellings with road traffic noise of more than 58 dB ( LDEN) are consid-ered
exposed to noise. When planning of new residential areas the national metric of
guideline for outside noise exposure is 58 dB ( LDEN). The Nordic prediction method,
Nord2000, is used for road traffic. The Noise Exposure Factor ( NEF) is the basis of all
cost- benefit analyses of noise from road traffic. NEF is an expression of the accumu-lated
noise load on all the dwellings in an area. It is calculated as the sum of the
weighted noise loads on the individual dwellings in the area, so that dwellings with
high noise levels weigh more than dwellings with less noise. The economic valuation
of noise effects are based on market prices of dwellings as well as health effects.
As an important part of planning new highway sections in Denmark, an Environ-mental
Impact Assessment ( EIA) study is performed. Noise is one of the environ-mental
components included in the EIA. When planning of new highways the noise
guideline of 58 dB as LDEN is used whenever possible. The guideline is used when a
group of houses/ dwellings are exposed to road traffic noise. For single houses in rural
districts the noise guideline is normally not taken into account, instead façade insula-tion
is offered if the noise exceeds 63 dB. Different measures of noise abatement can
be considered in the planning of new highways. If it is possible and realistic to locate
an alignment of the new highway that maximizes the distances to residential areas, this
is normally a preferable solution. Noise reducing pavements are normally used when a
new highway passes group of houses/ dwellings.
Like in new highway projects noise is also taken into consideration when enlarge-ments
of existing highways are planned.
6
During the last decade the Danish Road Directorate has used around 20 mill DKK
( 2.7 mill € or 3.6 mill USD) every year for noise abatement along the existing high-ways
and other state roads. Noise barriers have been the primarily tool applied for
noise abatement. In some situations where it has not been possible to use noise barri-ers
to achieve sufficient noise reduction, façade insulation has been used instead, typi-cally
by changing windows and doors to new and better noise reducing types.
In spring 2009 the Danish Road Directorate published a proposal for a new noise ac-tion
plan for the existing state road network. The purpose of the plan is to describe ini-tiatives
that are planned to reduce road traffic noise along the state road network
where the noise is considered unacceptable. The plan also describes noise initiatives in
relation to maintenance of the road network as well as the improvement and enlarge-ment
of the state road network.
Since the mid 1980 ´ s noise has been integrated in municipal land use planning. In the
planning process of new residential areas a land use plan has to be developed and ap-proved
by the local municipality. A noise guideline at dwellings of 55 dB ( LAeq, 24h) has
to be respected. In 2007 the noise indicator LDEN was introduced to replace LAeq, 24h and
the noise guideline was changed to 58 dB ( LDEN) to ensure the same protection level.
This report is produced by the Danish Road Directorate/ Danish Road Institute for
the California Department of Transportation. For comprehensive guidance on traffic
sound issues in California please reference Caltrans’ Technical Noise Supplement and
Traffic Noise Analysis Protocol manuals.
7
Sammenfatning
Når der bygges nye veje eller bygninger i Danmark tages der særlige hensyn til vejtra-fikstøj.
Et nyt nationalt støjkort viser, at omkring 30 % af danske hjem udsættes for
støj som overskrider den vejledende grænseværdi på 58 dB ( LDEN) og at støjproble-merne
hovedsageligt forekommer i byerne. Denne rapport præsenterer metoder og
strategier til støjbekæmpelse. Der findes ingen enkel metode for at fjerne alle støjpro-blemer
langs motorveje og i byer. Det er nødvendigt at anvende støjbekæmpelse på
forskellige niveauer:
• Ved kilden: dette dækker køretøjer, dæk, belægninger, trafik og hastighed.
• Under udbredselse: i form af støjskærme, etc.
• Ved modtageren: i form af facadeisolering og lokale skærme.
Baggrunden for denne rapport er erfaringer og idéer fra det danske Vejdirektorat samt
andre europæiske lande. Som en introduktion præsenteres 14 anbefalinger for ” good
governance” angående støjledelse og - bekæmpelse.
I Danmark anses boliger at være udsat for støj hvis niveauet er højere end 58 dB
( LDEN). Når der planlægges nye boligområder anvendes normalt en grænseværdi på 58
dB ( LDEN). Den nordiske støjberegningsmetode, Nord2000, anvendes for vejtrafik.
Støjbelastningstallet ( SBT) er grundlaget for økonomiske analyser af støj fra vejtrafik.
SBT er et udtryk af den samlede støjbelastning på alle boliger i et område. Det er be-regnet
som summen af de vægtede støjbelastninger på individuelle boliger i området,
således at boligerne med høje støjniveauer vægtes tungere end boliger med mindre
støj. Den økonomiske vurdering af støj er baseret på markedsværdien af boliger samt
indflydelsen på helbred.
Som en vigtig del af planlægning af nye motorvejsstrækninger i Danmark, udføres
normalt en VVM analyse. Støj er en af de miljømæssige faktorer, som tages med i
VVM undersøgelserne. Når der planlægges nye motorveje, bliver en støjgrænseværdi
på 58 dB som LDEN anvendt, hvis det er muligt. Grænseværdien anvendes, når en grup-pe
huse/ boliger er udsat for støj fra vejtrafik. For enkelte huse på landet, tages normalt
ikke hensyn til grænseværdien. Der tilbydes i stedet facadeisolering, såfremt støjen
overstigen 63 dB. Forskellige virkemidler til at reducere støjen kan anvendes, når der
planlægges nye motorveje. Hvis det er muligt og realistisk at finde an linjeføring for
den nye motorvej, som giver den maksimale afstand til boligområder, er det normalt
den foretrukne løsning. Støjreducerende belægninger bruges normalt, når en motorvej
passerer en gruppe huse/ boliger.
Som ved nye motorvejsprojekter, tages også støj i betragtning, når der planlægges en
udvidelse af eksisterende motorveje.
8
I løbet af den sidste 10- års periode har Vejdirektoratet gennemsnitlig brugt ca. 20 mio.
DKK (€ 2.7 mio. eller USD 3.6 mio.) hvert år på støjbekæmpelse langs eksisterende
motorveje og hovedlandsveje. Støjskærme er det vigtigste virkemidel. I nogle situatio-ner,
hvor det ikke har været muligt at anvende støjskærme for at opnå tilstrækkelig
støjreduktion, er facadeisolering anvendt, typisk ved at udskifte vinduer og døre til
mere støjreducerende typer.
I foråret 2009 udgav Vejdirektoratet et forslag for en ny støjhandlingsplan for det ek-sisterende
vejnet. Formålet med planen er at beskrive tiltag for at nedsætte vejstøj
langs statsvejene, der hvor støjniveauet anses for at værende uacceptabelt. Planen be-skriver
også støjinitiativer i forhold til vedligeholdelse og udvidelse af statens vejnet.
Siden midten af 1980’ erne er støj indgået i lokalplanlægningen i forbindelse med plan-lægning
og bygning af nye boliger. En støjgrænseværdi for boliger på 55 dB ( LAeq, 24h)
skal overholdes. I 2007 blev støjindikatoren LDEN introduceret som erstatning for
LAeq, 24h og støjgrænseværdien blev ændret til 58 dB ( LDEN) for at sikre samme beskyt-telsesniveau.
Denne rapport er udarbejdet at Vejdirektoratet/ Vejteknisk Institut i Danmark for Cali-fornia
Department of Transportation i USA.
9
Preface
Noise abatement is a big challenge for European and American transportation agen-cies.
Noise is an important factor to be considered when it comes to developing, upgrading
and maintaining national highway networks in Europe. Significant financial resources
are used to incorporate noise abatement measures in developing or upgrading national
highways. This report presents a series of methods and strategies for assessing and ad-dressing
noise impacts. The background for the report is procedures and experiences
from the Danish Road Directorate as wells from other European countries.
The project is carried out under the framework of the research technical agreement
titled “ Supplementary Studies for the Caltrans Quieter Pavement Research Program”
between California Department of Transportation ( Caltrans) and University of Cali-fornia
Pavement Research Centre ( UCPRC) as a part of the task: “ Policy documents:
guidelines for Caltrans policy”. The Danish Road Institute/ Road Directorate ( DRI-DK)
is subcontracted by UCPRC to work on the project.
Caltrans has asked DRI- DK to produce this brief catalogue of ideas on noise abate-ment
and integration of noise considerations when planning and constructing new
highways as well as when maintaining existing roads based on Danish experiences.
The use of different measures for noise abatement like implementing noise reducing
pavements, noise barriers, facade insulation, etc. are included. Land use planning and
design of new housing along existing highways as well as noise policies and strategies
will are also presented.
The report is compiled and written by Hans Bendtsen DRI- DK. Jakob Fryd from the
Planning Division of the Danish Road Directorate and Bruce Rymer from Caltrans,
Division of Environmental Analysis has given comments and advice. The author will
like to thank everybody who has made it possibly to compile this report for their ef-forts
and qualified work. This report is written from the Danish perspective and does
not represent official Caltrans policy. This report is produced by the Danish Road Di-rectorate/
Danish Road Institute for the California Department of Transportation. For
comprehensive guidance on noise issues in California please reference Caltrans’
Technical Noise Supplement [ 8] and Traffic Noise Analysis Protocol [ 9] manuals.
10
Forord
Støjproblemer er en stor udfordring for vejmyndighederne både i Europa og USA.
Støj er en vigtig faktor som indgår i forbindelse med nybygning, opgradering og ved-ligeholdelse
de nationale vejnetværk i Europa. Væsentlige økonomiske ressourcer an-vendes
på støjreducerende foranstaltninger. Denne rapport præsenterer en serie meto-der
og strategier for integration af støjhensyn i vejplanlægningen. Baggrunden for
denne rapport er metoder og erfaringer fra det danske Vejdirektorat samt andre euro-pæiske
lande.
Projektet er gennemført som en del af den tekniske forskningsaftale “ Supplementary
Studies for the Caltrans Quieter Pavement Research Program” mellem California De-partment
of Transportation ( Caltrans) og University of California Pavement Research
Centre ( UCPRC), som en del af opgaven: “ Policy documents: guidelines for Caltrans
policy”. Det danske Vejteknisk Institut/ Vejdirektorat er underleverandør til UCPRC
for at arbejde på projektet.
Caltrans har bedt Vejteknisk Institut/ Vejdirektorat om at producere dette idékatalog
om støjbekæmpelse og integrering af støjhensyn når der planlægges og bygges nye
motorveje samt i forbindelse med vedligeholdelse af eksisterende veje. Anvendelse af
forskellige virkemidler som støjreducerende belægninger, støjskærme, facade isole-ring
etc. er medtaget. Fysisk planlægning og design af nye boligområder langs eksiste-rende
motorveje såvel som politikker og strategier for støjbekæmpelse er også medta-get.
Rapporten er udarbejdet og skrevet af Hans Bendtsen Vejdirektorat/ Vejteknisk Insti-tut.
Jakob Fryd fra Planlægningsafdelingen i Vejdirektoratet i Danmark og Bruce Ry-mer
fra Caltrans, Division of Environmental Analysis har kommenteret rapporten.
Forfatteren vil gerne takke alle, som har gjort det muligt at udarbejde denne rapport.
Rapporten er skrevet fra et dansk perspektiv og præsenterer derfor ikke officiel
Caltrans politik.
11
1. Introduction
When constructing new buildings or roads in Denmark special consideration is given
to traffic noise. A new national noise map indicates that around 30 % of Danish
homes are exposed to noise levels that exceed the guideline value of 58 dB ( LDEN)
and that noise problems are concentrated in cities.
Road traffic noise may impact people in different ways such as impacting communica-tion,
and interrupting sleep. New studies show that noise can contribute to an in-creased
risk of cardio- vascular diseases. The effects of noise are also of an economic
nature because noise influence housing prices in areas exposed to noise. Furthermore,
health related issues caused by noise also incur costs. The socio- economic costs re-lated
to road traffic noise have been calculated to amount to between 0.8 and 1.2 bil-lion
Euro ( 1.1 to 1.6 billion USD) annually in Denmark [ 6].
1.1 Methods for noise abatement
Figure 1.1. Façade insulation by applying a “ glass box” in front of an existing window of bedroom
or living room. Example from an apartment building in Århus, Denmark [ 10].
There is no single method that can remove all noise problems along highways and in
cities. It will be necessary to address noise abatement on several different levels [ 7]:
• At the source: this covers vehicles tires, pavements, traffic, speed and driving
patterns. When noise is reduced at the source, it has an effect on all buildings and
open space areas that are affected by the noise along a given roadway section.
Noise reduction on pedestrian and bicycle paths along the road will also be an im-provement
for pedestrians and cyclists.
12
• Along the propagation path: in the form of noise barriers and berms. By using
noise barriers, a noise reduction will be experienced in buildings and open space
areas that are behind the barriers, but not for the areas in front of the barriers.
• At the receiver: in the form of façade insulation and local barriers. Façade insu-lation
is limited to reducing the noise level inside when the windows are closed,
whereas the noise level outside remains unaffected.
Additional methods can be applied to reduce noise such as barriers, noise reducing
pavements, traffic diversion, speed reductions, limiting heavy vehicle access at night,
vegetation, and façade insulation to name a few. Environmental zones with speed lim-its
can also be used to reduce noise levels.
1.2 Organisation of noise abatement
Often nothing is done to reduce noise problems, perhaps due to the fact that there of-ten
is no clear “ owner” of the problem or a lead organisation has not been identified to
take initiatives for improvements. Also, problems might seem overwhelming; there
could be a lack of useful ideas or alternatives to finance the proposed activities all re-sulting
in nothing being done. However, it is very important to support and stimulate
positive development, even though the hurdles seem insurmountable and the results in
the beginning are very limited.
To aid in initiating and carrying out the noise related work in the municipal authorities
or road administrations, a special noise secretariat could be established, whose em-ployees
would mainly deal with planning, initiating and managing the local efforts. A
concerted effort of different municipal departments and other affected parties such as
private citizens, owner and tenants’ associations and the business community is advis-able.
A municipal authority is a large organisation that continuously plans and implements
activities in the construction, running and maintenance fields. It could be considered a
municipal goal that traffic noise issues become an integral part in all relevant activities
such as road maintenance, building maintenance and renovation of open space areas
and parks.
City planning and possible adjustments within existing urban areas are tasks that are
handled by the municipal authorities. Noise is an important parameter that is normally
taken into consideration when building new housing areas. However, it would also be
useful to include noise as a parameter when addressing issues such as rebuilding and
expanding housing areas as well as in projects on rebuilding and widening roads or
traffic calming. A starting point could be drawing up a set of municipal goals for noise
related issues in existing urban areas.
There is a need to activate as many assets as possible for the work to reduce noise. A
municipal authority can play an important role in relation to private citizens and the
business community. Danish research shows that in certain cases private citizens are
willing to participate in funding noise reducing measures [ 34]. It is important to in-form
citizens of the technical and economic possibilities as these are not always com-mon
knowledge.
13
A noise secretariat can play an important role as an “ idea bank”, initiative taker, and
coordinator. In this forum one could gather citizens affected by noise and present them
with technical solutions as well as helping them to organise noise reducing efforts that
could be achieved and paid for, either in part or fully, by the house owners and the
citizens themselves. The municipal efforts could consist of organisation and coordina-tion
with a view to activating the assets and resources available amongst the citizens,
and also to take part in the carrying out of certain tasks. Furthermore the possibility to
share the costs of certain activities could be examined.
Figure 1.2. When fences at residential areas are to be renewed by the owner they can be con-structed
as noise barriers. This might not increase the cost significantly but the noise has to be con-sidered
when selecting design, construction and material for the new fence [ 10].
There are several examples from both Denmark and abroad that show how road traffic
noise reducing projects have been financed [ 35]. House owners can implement noise
reducing measures at their own homes at their own cost. A rise in property value as a
result of the noise reducing measures can motivate some home owners to finance these
measures themselves. Depending on the current tax situation, increased property val-ues
mean that the both the state and the municipality receive increased taxes, that can
again be reinvested in other noise reducing projects. In apartment buildings noise re-duction
can be achieved by changing to specialized noise insulating windows that can
be financed over the annual maintenance budget that could also be used to finance
other noise reducing projects.
14
Figure 1.3. When the windows of apartment buildings and single family houses along highways
have to be replaced by the owner, noise can be taken into consideration when selecting the new
windows. Without a significant increase in cost, improved noise reduction and energy reductions
can often be achieved [ 10].
Figure 1.4: Public meeting on noise abatement etc in relation to a highway project.
In connection with noise reducing projects that are planned, it can be recommended to
involve those citizens that will be affected by these projects. This will give the citizens
influence on which solutions that will be chosen and give them a realistic picture of
which level of noise reduction to expect. Citizens can become actively involved and in
some cases even be joint partners in the planned projects. Involved citizens might be-come
motivated to implement further measures which can improve the effect and
quality of the planned improvements.
15
1.3 Structure of the report
As an introduction, fourteen recommendations to National Road Administrations for
good governance regarding noise management and abatement are presented in Chapter
2. Noise guidelines, prediction of noise and socio- economic evaluation of noise are in-troduced
in Chapter 3. This is followed by three typical planning situations where
noise can be considered in relation to highways:
• Planning of new highways in Chapter 4.
• Planning of widening existing highways in Chapter 5.
• Noise abatement at existing highways in Chapter 6.
Finally Chapter 7 presents, how noise is taken into consideration when building new
residential areas along highways.
All the noise levels presented in this report are A- weighted. The unit “ dB” is used in
this report and it is equal to what is often denoted “ dB( A)” and “ dBA”. The following
exchange rates are assumed in this report: 1 € = 7.45 DKK and 1 USD = 5.50 DKK.
16
17
2. Good governance in noise abatement
The following fourteen recommendations to National Road Administrations ( NRA)
for good governance regarding noise management and abatement [ 3] were developed
by a European noise group from the Conference of European Directors of Roads
( CEDR) [ 5]:
1. In Europe, the main noise problems occur along the existing road network and
the order of magnitude of the problems is increasing with increasing traffic vol-ume.
Therefore, noise abatement along these roads is crucial in order to start a
process where the noise exposure over the long term is reduced.
2. It is important to include noise issues at the early planning stage for new road
developments. In adopting such an approach, future noise problems may be
avoided. The basis for such an approach will normally be the national noise
guidelines.
3. Noise should be included as an important parameter in projects where existing
roads are improved to accommodate increasing traffic volumes or increasing
speeds. This can improve the noise environment for people living in close prox-imity
to the upgraded road.
4. When planning to incorporate noise abatement measures on new, existing and
reconstructed roads, it is important to adopt a time horizon of 20 to 30 years,
when predicting future noise from increasing traffic volumes and planning noise
measures. This will enhance the robustness of specific noise projects.
5. When road construction work is carried out in close proximity to residential
areas, it is relevant to consider construction noise when planning and realizing
such works. Residents close to the construction site should get sufficient infor-mation.
6. In projects where noise abatement measures are planned and designed, it is
recommended to establish a good communication strategy to ensure a two way
communication process with the public. In this way, residents may take owner-ship
of the project and their expectations to what noise mitigation may deliver
in terms of noise reductions may be more realistic.
7. Noise barriers erected on roads have not only visual impacts for the residents
living in close proximity to the road but also the driver and their passengers.
It is therefore, important to use barrier designs that are appropriate to the spe-cific
location where they are installed.
8. The use of noise reducing pavements should be considered when selecting
noise mitigation measures because such pavements are purported to provide
a cost effective tool in noise abatement. In upgrading existing roads, the use
of noise reducing pavements is often a low cost measure of noise abatement.
18
9. Integration of noise as an active component in Pavement Management Systems
can increase the optimal use of noise reducing pavements in the ongoing road
pavement renewal process.
10. To enhance the current market for noise reducing pavements the development
and use of a noise labeling system in member states should be considered.
11. In order to reduce noise emissions from individual vehicles, it would be invalu-able
if individual NRAs lobby at EU level to promote tighter noise limits for
the EU type approval of new vehicles and tires.
12. Like all elements of infrastructure, noise abatement measures such as pave-ments,
barriers, façades, etc. need to be maintained on a regular basis.
13. There is a need for further research and development in improved and long time
durable measures of noise abatement like optimized noise reducing pavements,
tires, vehicles etc.
14. A continuation of international cooperation on noise abatement and manage-ment
between the NRAs is value adding and fruitful. In the coming years issues
like noise mapping and noise action plans in relation to European Noise Direc-tive
( END) [ 22] seems highly relevant.
Figure 2.1. When road construction work is carried out in close proximity to residential areas, it is
relevant to consider construction noise when planning and realizing such works.
19
3. Guidelines, prediction and evaluation
3.1 Noise guidelines
For many years, the noise indicator LAeq, 24h has been used in Denmark when assessing
noise from road traffic. LAeq, 24h is an expression of the “ average” noise level over the
24 hours of the day. The guideline for noise exposure outside at the façade of residen-tial
buildings has been 55 dB ( not including the noise reflected from the façade).
On the background of a European Union Directive on environmental noise [ 22] the
new indicator LDEN was introduced by the Environmental Protection Agency in 2007
in a new guideline on road traffic noise [ 23]. For LDEN the noise ( as LAeq) is predicted
for the day, evening and night period. 5 dB is added to the evening time level and 10
dB is added to the night level in order to make a kind of compensation for when peo-ple
are more sensitive to noise than during daytime. The three time periods are in Den-mark
defined as:
• Day: 07 – 19, length 12 hours
• Evening: 19 – 22, length 3 hours
• Night: 22 – 07, length 9 hours
LDEN is then calculated as the weighted sum of the adjusted noise levels for the three
periods of the day using the below formula:
LDEN = 10 log { 12 · 10Lday/ 10 + 3 · 10( Levening+ 5)/ 10 + 9 · 10( Lnight+ 10)/ 10} ( 1)
According to [ 23] for Danish conditions with a “ normal” distribution of the traffic
over the 24 hours of the day LDEN can be predicted by adding 3 dB to LAeq, 24h :
LDEN = LAeq, 24h + 3dB ( 2)
Therefore the existing noise guide lines were adjusted by 3 dB when LDEN was intro-duced
in order to maintain the same level of noise protection as when LAeq, 24h was
used. In other European countries other relations between LDEN and LAeq, 24h are used
[ 3].
20
Table 3.1. Danish noise guidelines for road traffic noise expressed as L DEN [ 23].
Type of area Guideline LDEN
Recreational areas at the countryside, summer house areas, camp-sites
etc.
53 dB
Residential areas, kindergartens, schools and education facilities,
homes for elderly people, hospitals etc.
Allotment gardens, outside recreational areas and parks.
58 dB
Hotels and offices etc. 63 dB
The new Danish noise guidelines for road traffic noise, expressed as LDEN, can be
seen in Table 3.1. It must be emphasised that it is guidelines and not mandatory noise
levels that must not be exceeded anywhere along the highway and road network.
These guidelines are generally used when planning and constructing new residential
areas etc, but are also taken into account when planning new roads and highways.
Noise metrics and guidelines are not consistent throughout Europe and a report from
CEDR [ 3] gives an overview of noise guidelines used in different European countries.
Denmark is currently in a transition period where LAeq, 24h has been replaced with
LDEN. This is reflected in this report, where some examples use LAeq, 24h and other
examples use LDEN.
3.2 Noise prediction
In Denmark, the Nordic model for road traffic noise has been the official prediction
method since the 1970s. In 2007 the Environmental Protection Agency [ 23] intro-duced
a new version called Nord2000 [ 25, 26] which was developed as a joint Nordic
project. Nord2000 is a completely new model and in principle there are no links to the
old model. Both the source data and propagation model are new components.
The idea was to develop a general sound propagation model and source- specific
prediction methods for road and rail traffic as well as other types of environmental
noise sources. Nord2000 now consists of source models for road and rail traffic and a
propagation model. The model works in 1/ 3 octave bands and for any normal weather
type. Noise levels – for historical reasons – have been computed for different weather
conditions in the earlier Nordic models. Now all types of environmental ( road and rail
etc) noise can be computed for the same weather.
The source model distinguishes between: 1) light, 2) medium and 3) heavy vehicles.
The 1/ 3 octave- band sound power level of each source is calculated from input pa-rameters
selected by the user, determining the sound power of tire/ road noise and pro-pulsion
noise, respectively. The noise emission data are based on comprehensive way-side
noise measurements. The Danish noise emission data are based on measurements
taken during 1999 – 2000 of 4000 vehicle pass bys at 21 sites with speed limits of 30 -
110 km/ h on pavements of 2 – 18 year old dense asphalt concrete or stone mastic as-phalt
and constructed with 8 – 12 mm maximum aggregate.
21
Emission levels of the new data set tend to be higher than in the former 1996 version
of the Nordic method. It is not clear whether the higher emission values are due to
changes in vehicle fleet or tyres.
The propagation model is based on geometrical ray theory and gives algorithms for
computing 1/ 3 octave band sound attenuation along the path from source to receiver
taking into account the terrain shape as well as ground type ( impedance) and rough-ness.
Nord2000 deals with attenuation under different weather conditions and is suited for
computing yearly average noise levels. Various classes of weather have been defined
and their frequency of occurrence has been determined based on data from meteoro-logical
observations. The yearly average is obtained by computing the noise level for
each weather class and then combining these levels weighted with their occurrence.
For example: the effect of using precise weather conditions at 300 m from a road with
a North- South alignment, the yearly average noise level in Denmark is 2 dB higher at
receivers east of the road than at receivers west of the road. The reason for the differ-ence
is that the most common wind direction is from the west. The NORD2000 model
predicts outdoor noise levels and does not specifically deal with indoor noise.
The Nord2000 method is developed for the environmental and transportation authori-ties
of the Nordic countries. This taxpayer- developed method consists of a users guide
[ 26] and a large series of formulas that are available for free ( see reference list of
[ 26]). It is the challenge of private software companies on the open market to provide
commercial computer based versions of Nord2000. Currently, there are commercial
software products based on the NORD2000 model available on the market. But in or-der
to make NORD2000 available to governmental authorities and the public that sup-ported
its development, a simple or ‘ lite’ version of the Nordic model is available. The
‘ lite’ version covers a series of typical standard cases for roads, barriers and geometry
with pre- calculated transfer functions for 30 selected cases. Default traffic data for
five typical types of road configurations can be edited by the user to fit any specific
case. This PC version is working in English language and can be downloaded free of
charge from [ 27]. The user has to define input data like traffic, distribution of traffic
over the day, road surface type, noise barriers etc.
22
Figure 3.1. “ Front page” of the simple PC program for the Nord2000 road traffic noise prediction
method used in Denmark and the other Nordic countries [ 27].
The free downloadable version of the software communicates with a server in Norway
with a huge database of pre- predicted results. The results are outdoor noise levels and
they can be delivered as LAeq, 24h, LDEN, Lnight and LAFmax. In this way road, traffic and
town planners have easy access to Nord2000.
3.3 The Noise Exposure Factor
The Noise Exposure Factor ( NEF – in Danish “ Støjbelastningstal”, “ SBT”) is the basis
of all Danish cost- benefit analyses of noise from road and rail traffic [ 11]. It is an ex-pression
of the accumulated noise load on all the dwellings in an area. It is calculated
as the sum of the weighted noise loads on the individual dwellings in the area, so that
dwellings with high noise levels weigh more than dwellings with less noise.
Calculations of the NEF are based on noise levels in three locations around a dwelling:
inside the dwelling, outside the dwelling, and at outdoor activity areas connected to
the dwelling. The noise level outside the dwelling is calculated as free- field values on
the facade and can be interpreted as the noise level to which the inhabitants are ex-posed,
when the windows are open. The weight assigned to each of these situations
depends on how often it is occupied and whether it is an ordinary dwelling or a week-end
cottage/ summer house.
23
The weights can be seen in Table 3.2. The method to calculate NEF values has been
developed when LAeq, 24h was used as the noise indicator. In order to use the method
for noise predicted as LDEN 3 dB has to be added to all the noise intervals in Table 3.3
and 3.4.
Table 3.2. Weight assigned to various situations when calculating NEF [ 14].
Outside dwelling Outdoor areas Inside dwelling
Ordinary dwelling 0.2 0.2 0.6
Weekend cottage etc. 0.1 0.3 0.1
Figure 3.2. The relationship between the annoyance factor and the noise outside ordinary dwell-ings.
Noise levels are free- field levels on the façade [ 11, 14].
The NEF is based on a dose- response relationship given by:
Annoyance factor = 0.01 * 4.220.1( LAeq - K) ( 3)
Where:
K = 16 and LAeq starts at 30 dB for noise inside dwellings.
K = 41 and LAeq starts at 55 dB for noise outside ordinary dwellings.
K = 36 and LAeq starts at 50 dB for noise outside weekend cottages etc.
The actual annoyance factor for a specific noise level is derived from a dose- response
relationship for noise outside ordinary dwellings. The relation between the annoyance
factor and the noise levels is shown in Figure 3.2.
24
The number of dwellings subjected to noise in each of the three situations are calcu-lated
in intervals of 5 dB using the NORD2000 noise prediction method ( see Section
3.2) and multiplied by the corresponding annoyance factor ( Table 3.3). The resulting
values are summed and multiplied by the corresponding weight from Table 3.2 to give
the NEF for the situation for the type of dwelling. Finally the total NEF is calculated
by adding the values for each situation and each type of dwelling. An example for cal-culating
the NEF for ordinary dwellings is shown in Table 3.4.
Written as a formula, the NEF can be calculated as:
ijk ijk
k i
jk
j
NEF = Σ Σ w Σ a N ( 4)
Where:
k = ord, wec ( ordinary dwelling, weekend cottage).
j = od, oa, in ( outside dwelling, outdoor areas, onside dwelling).
i = 1, 2, 3, 4, 5, 6 ( 5- dB intervals starting at 30 dB, 55 dB or 50 dB,
see table 3.3).
wjk = { 0.2, 0.2, 0.6} k= ordinary dwelling, { 0.1, 0.3, 0.1} k= weekend cottage.
aijk = 0.11, 0.22, 0.45, 0.93, 1.92, 3.94.
Nijk is the number of dwellings in the various 5- dB intervals
Table 3.3. Annoyance factor for the individual dwellings [ 14].
Type of area
Ordinary dwelling Weekend cottage etc
Noise level
in dB Indoors Outside Indoors Outside
30.1- 35.0 0.11 - 0.11 -
35.1- 40.0 0.22 - 0.22 -
40.1- 45.0 0.45 - 0.45 -
45.1- 50.0 0.93 - 0.93 -
50.1- 55.0 1.92 - 1.92 0.11
55.1- 60.0 3.94 0.11 3.94 0.22
60,1- 65.0 - 0.22 - 0.45
65.1- 70.0 - 0.45 - 0.93
70.1- 75- 0 - 0.93 - 1.92
75.1- 80.0 - 1.92 - 3.94
25
The NEF makes it possible to compare the benefits of different noise reducing strate-gies
such as barriers, pavements, and sound insulation in a manner that accounts for
the differences in where the noise is reduced. This accounting approach allows several
different noise mitigation strategies and combinations of strategies to be compared
more equitably. In practice however, NEF- calculations are usually simplified using
only the noise level outside the façade of dwellings and assigning this the weight 1,
thus omitting the separate valuation of indoor noise and noise on outdoor areas.
Table 3.4. Example of a calculation of NEF for ordinary dwellings [ 11].
Outside dwellings Outdoor areas Inside dwellings
Noise at
façade
[ dB]
No. of
dwellings
Annoy.
factor
Noise
outside
[ dB]
No. of
dwellings
Annoy.
factor
Noise
inside
[ dB]
No. of
dwellings
An-noy.
factor
65- 70 163 00.45 65- 70 37 0.45 40- 45 163 00.45
60- 65 207 00.22 60- 65 15 0.22 35- 40 207 00.22
55- 60 123 00.11 55- 60 19 0.11 30- 35 123 00.11
Weight 00.2 Weight 0.2 Weight 00.6
NEF 26.5 NEF 4.4 NEF 79.4
Sum of NEF = 110.3
By using this simplification, it is not possibly to make a correct evaluation of the ef-fect
of establishing façade insulation as a tool for noise abatement, and evaluations of
noise barriers may also be misleading due to actual differences in noise levels at the
façade and on the outdoor areas.
3.4 Socio- economic assessment of noise
In 1999, the Danish Ministry of Finance published a guide to preparing socio-economic
assessment of consequences [ 12] of construction works etc. The aim of this
was to achieve greater uniformity in socio- economic assessments of initiatives in the
traffic and energy sectors and in relation to investments in administration buildings
and investments in the educational sector. The choice of Cost- Benefit Analysis ( CBA)
or of cost- effectiveness assessment ( CEA) depends on the characteristics of the initia-tive,
but CBA is presented as the primary method [ 12].
The guidelines contain standards and principles for calculation of central parameters
in the analyses. Valuation should be based on net present value using a calculation in-terest
rate of 6 percent and a 20 % tax cost factor to account for the costs to society
due to financing through taxes. For projects with time horizons of more than 20 years
the tax cost factor can be left out if a calculation interest rate of 7 percent is used.
26
In 2003, the Ministry of Transport published a manual for socio- economic analysis
based on the above guidelines from the Ministry of Finance [ 13]. The assessment of
noise is based on annoyance at dwellings whereas noise at occupational buildings and
institutions is not included. Noise levels below 55 dB ( LAeq, 24h) are not included and
there is no differentiation between day and night time noise. This relates to the Danish
guideline value for road traffic noise at dwellings which is 55 dB ( LAeq, 24h).
Valuation of noise effects are based on market prices. Ministry of Transport continu-ously
publishes a catalogue of key values for use in analyzes. In the 2004 version of
the catalogue [ 15], the values put on noise are based on a new house price survey ( the
hedonic method) [ 16]. The value put on noise annoyance is 35,853 DKK ( 4,812 € or
6519 USD) per NEF ( 2003 price level). 23,018 DKK ( 3,090 € or 4185 USD) per NEF
is added for costs to society due to health effects, which are not included in the re-duced
house prices. The total value of noise is thus 58,871 DKK ( 7,902 € or 10704
USD) per NEF ( 2003 price level).
The assessment of health effects is based on a study of the international literature on
the subject [ 17]. It is concluded that the documentation of actual health effects of
noise from road traffic is weak and without clear evidence, and the estimates of costs
are therefore done with reservation. There is some evidence of a connection between
noise and ischaemic heart disease, although the risk factors related to it are uncertain.
A risk factor of 1.09 per 5 dB increase in noise levels is adopted, and it is decided also
to use this factor for hypertension. Other possible health effects are left out of the as-sessment
of costs.
The catalogue [ 15] also presents marginal costs of noise from transportation. The
noise costs per driven vehicle kilometre ( 2003 price level) can be seen in Table 3.5.
The uncertainty on these values is estimated to be minus 50% to plus 100%.
Table 3.5. Danish estimated noise costs per driven vehicle kilometre ( 2003 price level) [ 15].
Vehicle type DKK/ km €/ km USD/ km
Passenger cars 0.12 0.016 0.022
Light Goods Vehicle 0.17 0.023 0.031
Heavy Goods Vehicle 0.25 0.034 0.046
Bus 0.55 0.074 0.100
This subject of socio- economic costs of noise is discussed more in the DRI- DK report
“ Cost- benefit analysis on noise- reducing pavements” [ 11].
27
4. Planning of new highways
As an important part of planning new highway sections in Denmark, an Environ-mental
Impact Assessment ( EIA) study is performed. Noise is normally one of the
environmental components included in the EIA.
4.1 An example
Figure 4.1. Planning of a new highway between Ølholm and Vejle. Noise mapping of the reference
situation in 2015 at a receiver height of 1 ½ m ( 5 feet). The noise contours along the existing road
are presented [ 21].
The following is an example of how noise was handled in the EIA [ 21] conducted as a
part of planning a new highway in Denmark between Ølholm and Vejle. In this exam-ple,
LAeq, 24h is used as the indicator for noise.
28
For the existing road network with no new highway, the noise was mapped for 2015
taking into consideration an increase in traffic - this is called the reference situation.
The existing road network includes the existing highway carrying the main traffic as
well as the other roads in the district that will have a change ( primarily reduction) of
traffic of 15 % or more if the new highway is constructed. Three different traces for
the new highway have been evaluated:
• Main Solution (“ Hovedforslag” in Danish).
• Alternative 1.
• Alternative 2.
Noise mapping has been conducted for these four situations using the LAeq, 24h noise in-dicator.
The noise maps can be seen in Figures 4.1, 4.2 and 4.3.
Figure 4.2. Planning of a new highway between Ølholm and Vejle. Noise mapping of the Main So-lution
in 2015 at a receiver height of 1 ½ m ( 5 feet). The noise contours along the existing road as
well as the suggested new highway is presented [ 21].
29
Figure 4.3. Planning of a new highway between Ølholm and Vejle. Noise mapping of Alternative 2
in 2015 at a receiver height of 1 ½ m ( 5 feet). The noise contours along the Alternative 2 alignment
of the new highway and the existing road are presented [ 21].
The number of dwellings exposed to different noise levels has been counted on the
background of the noise mapping and the Noise Exposure Factor ( NEF) which has
been predicted ( see Table 4.1).
30
Table 4.1. Summary of noise mapping. Number of dwellings exposed to noise, the NEF and the
change of NET in relation to the reference situation [ 21].
Total of noise exposed dwellings NEF Change
in NEF
Scenario
55- 60
dB
60- 65
dB
65- 70
dB
> 70
dB
Total
Reference 272 153 197 38 660 153.8 -
Main Solution 189 159 214 0 562 122.3 31.5
Alternative 1 201 132 222 0 555 116.2 37.6
Alternative 2 222 133 221 0 576 119.2 34.6
In the reference situation, 660 dwellings along the road network being studied, are ex-posed
to more than 55 dB. This represents a NEF value of 153.8. In the main solution
this is reduced by 98 to 562 dwellings with a reduction of NEF by 31.5. Alternative 1
and 2 represents slightly higher reductions of NEF of respectively 37.6 and 34.6. The
EIA [ 21] discusses noise barriers, noise reducing pavements and wide greenbelts as
possible measures of noise abatement, but at this state in the planning process no deci-sions
were taken on which measures of noise abatement to implement.
4.2 General measures of noise abatement
The old noise guideline of 55 dB LAeq, 24h was replaced in 2007 with 58 dB LDEN for use
in the planning of new highways. The guideline is used when a group of houses/
dwellings are exposed to road traffic noise. For a single, isolated house in rural dis-tricts,
the noise guideline is normally not taken into consideration. Instead façade insu-lation
is offered to the owners if the noise exceeds 63 dB.
Different measures of noise abatement can be considered in the planning of new
highways. If it is possible and realistic to locate an alignment of the new highway that
ensures long distances to residential areas, this is a preferred solution. But there can
be other environmental, technical and/ or economical factors that also have to be taken
into consideration and which also have an influence on the final decision of the align-ment
of the new highway through the terrain and urban areas. The following measures
of noise abatement are often considered:
• Placing the highway in a cutting and maybe using the surplus soil/ material to estab-lish
embankments along the highway.
• Noise barriers and earth walls.
• Total covering of the highway by a applying a cut and cover process.
• Noise reducing asphalt pavements have been more commonly used in recent years.
• Offer façade insulation to the house/ dwelling owners ( see Section 6.1).
31
• In limited cases, the road administrations might buy houses with high noise
exposure and either demolish the buildings or rebuild the structures for less- noise-sensitive
commercial use.
• Using a wide belt of vegetation that has a dense appearance all year round.
The actual noise reducing effects of using these measures are normally assessed using
the NORD2000 noise prediction method ( see Section 3.2).
Figure 4.4. Combination of wave shaped concrete noise barrier and green noise barrier con-structed
as a “ supported” earth wall along the new ring road in Århus, Denmark.
Figure 4.5. 700 m long section of the new highway to Copenhagen airport, Denmark was con-structed
as a cut and cover strategy in order to reduce the noise exposure for some nearby multi-storey
apartment buildings.
32
Figure 4.6. Noise insulation of an apartment building by applying glass to cover the façade of the
balconies.
Figure 4.7. Close up photo of glass covered balconies. It is possible for the residents to open up the
balconies.
33
5. Planning of widening existing
highways
The Danish highway network is primarily developed as four lane roads. Due to in-crease
in traffic, some of the highway sections are being increased to six lanes. One
of the projects that was finalized in 2008 is the enlargement of the M3 highway [ 24].
The M3 is a highway, which functions as a ring road around Copenhagen as well as
being part of the E47/ E55 European corridor, which connects Sweden and Germany.
Being the only ring road around Copenhagen, which is built fully as a motorway, the
Average Daily Traffic on the two lanes in each direction is as high as 75,000 vehicles.
Congestion is frequent, and during rush hours travelling speeds of 25- 30 km/ h are
normal. In order to improve the traffic situation, it has been decided to widen the M3
from four to six lanes.
The M3 highway passes through densely populated residential districts. As part of
the planning of the extension, an Environmental Impact Assessment ( EIA) has been
carried out, including noise mappings and planning of noise abatement measures.
The Road Directorate, which is responsible for the extension, has made a great effort
to inform and reach out to the neighbours of the highway.
Figure 5.1. Highway M3 passes through densely built up residential areas around Copenhagen.
34
5.1 Environmental Impact Assessment
An Environmental Impact Assessment study [ 19] has been carried out in relation to
the road enlargement project considering the following factors:
• Population
• Landscape
• Culture and history
• Flora and Fauna
• Water resources
• Green areas
• Energy and CO2
• Air pollution
• Health effects
• Noise and vibrations
• Use of resources and waste production
• Light and reflections
• Soil and contaminated soil
Noise mapping has been performed for the existing situation including the noise con-tribution
from other main roads in the area. In this example LAeq, 24h is used as the indi-cator
for noise. On the background of the noise mapping, the consequences of using
noise barriers with different height have been analysed. Table 5.1 shows a summary of
the results. In the exiting situation 10,305 dwellings were exposed to more than 55 dB
equivalent to a Noise Exposure Factor ( NEF) value of 1717. By using noise barriers of
respectively 3, 4 and 5 meters height, reductions of NEF by 149, 630 and 769 can be
achieved.
Table 5.1. Evaluation of the effect on noise exposed dwellings and the NEF value to use 3,4 and
5 m high noise barriers along M3 [ 20].
Scenario Number of noise exposed dwellings
55- 60
dB
60- 64
dB
65- 69
dB
> 70
dB
Total noise
exposed
dwellings
Total
NEF
ΔNEF
Existing 6503 3244 482 76 10305 1717 -
3m barrier 5472 2985 526 78 9061 1568 149
4m barrier 4766 1890 253 36 6945 1087 630
5m barrier 4027 1663 238 35 5963 948 769
35
Table 5.2. Evaluation of the price and cost effectiveness of the different barrier solutions [ 20].
Scenario Price per
m2 in
DKK
Total
price in
mill. DKK
Total
price in
mill. €
Total
price in
mill. USD
ΔNEF ΔNEF
per 1
mill. DKK
3m barrier 2600 138 19 25 149 1.1
4m barrier 2380 169 23 31 630 3.7
5m barrier 2400 212 28 39 769 3.6
In order to evaluate the cost effectiveness of noise barriers with different heights,
the ΔNEF per mill. DKK invested has been predicted ( see Table 5.2). The predictions
show that a 1 mill. DKK investment in a 3 m high noise barrier gives a NEF reduction
of 1.1 and for a 4 m high barrier the reduction in NEF is 3.7 per million DKK in-vested.
The 4 m high noise barrier is in this prediction slightly more cost effective
than the 5 m barrier and the total investment needed for 4 m barriers is 169 mill. DKK
(€ 23 mill. or USD 31 mill. ) whereas the total investment for 5 m barriers will be
212 mill. DKK (€ 28 mill. or USD 39 mill.).
The cost effectiveness study supported a decision to use a combination of 3 and 4 m
high noise barriers. The consequence of this solution was a reduction of the total NEF
value by 677 at a total noise barrier cost of 162 mill. DKK (€ 22 mill. or USD 29 mill.)
and with a NEF reduction of 4.2 per 1 mill. DKK invested in noise barriers.
On the background of the Environmental Impact Assessment and an evaluation of cost
effectiveness, it was decided in this specific project to use 60 dB ( LAeq, 24) as the noise
guideline for the noise exposure from the M3 highway. 60 dB represents a significant
reduction in noise for many of the dwellings situated along the M3 highway. In order
to achieve 60 dB, the following measures have been implemented:
• 17,900 m of noise barriers have been constructed.
• Noise reducing pavements have been used.
Where these measures have not been enough to achieve 60 dB noise levels from the
highway noise exposure, façade insulation has been offered to the owners.
36
Figure 5.2. 3 to 4 m high noise barriers have been constructed along highway M3 as part of the
enlargement project.
5.2 Evaluation of noise reducing pavements
In order to evaluate the effect of using a noise reducing pavement on M3 instead of
the normally used Dense Grade Asphalt Concrete or a Split Mastic Asphalt, some
calculations have been performed on the background of the noise mapping analysis
along highway M3. The background for these calculations is the noise mapping of all
the dwellings affected by noise levels exceeding 55 dB in the initial situation after the
( widening) enlargement of the M3 highway with a standard pavement. Four scenarios
with a noise reduction of 1, 2, 3 or 4 dB have been included. Special types of noise re-ducing
pavements were not specified in this evaluation.
Table 5.3. Results of using noise reducing pavements on the noise exposure along M3. The results
are given as the number of dwellings exposed to different noise levels and the corresponding noise
exposure factor ( NEF) [ 18].
Scenario Number of noise exposed dwellings
55- 60
dB
60- 64
dB
65- 69
dB
> 70
dB
Total noise
exposed
dwellings
Total
NEF
ΔNEF
Standard 4343 1815 292 34 6484 1040 -
- 1 dB 3811 1788 197 34 5830 933 107
- 2 dB 3285 1705 196 34 5220 856 184
- 3 dB 3165 1376 189 34 4764 768 272
- 4 dB 2860 1368 188 34 4450 732 308
The results can be seen in Table 5.3. A total of 6484 dwellings are exposed to noise
over 55 dB in the situation using the standard pavement. This represents a total NEF
value of 1040.
37
By using a 2 dB noise reducing pavement, the number of noise exposed dwellings is
reduced by 933 and the NEF value is reduced by 184 to 856. Using the pavement with
4 dB noise reduction, the number of noise exposed homes is reduced
to 4450 and the NEF value is reduced by 308.
Table 5.4. Value of noise reductions caused by the use of pavements with different noise reduction
along the M3 expressed as the annual value in ( 2001 price level) and the net present value [ 18].
Scenario ΔNEF Annual value of noise reduction Net Present Value
Mill.
DKK
Mill.
€
Mill.
USD
Mill.
DKK
Mill.
€
Mill.
USD
- 1 dB 107 5.7 0.8 1.0 85 11 15
- 2 dB 184 9.7 1.3 1.8 146 20 27
- 3 dB 272 14.4 1.9 2.6 216 29 39
- 4 dB 308 16.4 2.1 3.0 244 33 44
The economic benefits from using noise reducing pavements are calculated, based
on the reduction in the NEF value achieved for the four scenarios for noise reducing
pavements. The calculations are done for noise reductions of 1 to 4 dB. The annual
value of the noise reductions is predicted by using the price per NEF unit presented
in section 3.4. The results can be seen in Table 5.4. A 2 dB noise reducing pavement
is in this project equivalent of a yearly saving of 9.7 mill. DKK ( 1.3 mill. € or 1.8 mill.
USD) due to reduced noise exposure on the dwellings around the highway. This corre-sponds
to a net present value of 146 mill. DKK (€ 20 mill. or USD 27 mill.). These
figures can be used in a Cost Benefit Analyses. An example of such an analyses can
be seen in “ Cost- benefit analysis on noise- reducing pavements” [ 11] from DRI- DK.
Figure 5.3. Noise reducing pavements were applied on the M3 highway.
38
Figure 5.4. Close up of the noise barriers designed for the M3 project ( roadside left and urban side
right).
39
6. Noise abatement on existing highways
During the last decade the Danish Road Directorate has used around 20 mill. DKK
( 2.7 mill € or 3.6 mill USD) every year for noise abatement along the existing high-ways
and other state roads. Noise barriers has been the primarily tool applied for noise
abatement [ 2].
Figure 6.1. Wooden noise barrier constructed along an existing Danish highway [ 2].
6.1 Façade insulation
In some situations where it has not been possible to use noise barriers to achieve suffi-cient
noise reduction façade insulation has been used instead, typically by changing
windows and doors to new and better noise reducing types ( and often also heat insula-tion
saving energy). Subsidies for noise insulation can be given to bedrooms, living
rooms and kitchens with a dining table. An indoor noise reduction of at least 5 dB
must be obtained and the resulting indoor noise level must not exceed 30 dB. The
Road Directorate does not carry out work on private properties. Instead the Road Di-rectorate
contacts the owners of the impacted dwellings and offers to pay them for
noise insulation. If the owners accept the offer the procedure is the following [ 28]:
• An acoustical consultant inspects the building and describes what kind of noise in-sulation
has to be carried out.
• The owner gets a price for the work from a private contractor.
• The Road Directorate has to accept the price.
• The owner orders the contractor to carry out the work.
40
• An acoustical consultant inspects and approves the work carried out.
• The owner pays the contractor.
• The owner sends the invoice to the Road Directorate for reimbursement.
The Road Directorate does not accept projects that cost more than 96,600 DKK
including VAT (€ 13,999 or USD 17,600) per dwelling for reimbursement ( price
level 2004). The reimbursement depends on the actual noise level as can bee seen
in Table 6.1. For noise levels over 70 dB ( LAeq24, h) the percentage is 90. The owner
of the dwelling does not have to pay income tax on the money received from the Road
Directorate for noise insulation.
Table 6.1. Reimbursement of costs of façade insulation against noise from the Road Directorate in
approved projects [ 28].
Noise zone ( LAeq24, h) Noise level Reimbursement percentage
Zone 1 > 70 dB 90 %
Zone 2 65 – 70 dB 75 %
Zone 3 60 – 65 dB 50 %
Figure 6.2. Façade insulation against noise has been carried out at dwellings along the Danish
highway network and the Road Directorate has reimbursed parts of the costs.
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Figure 6.3. Elevated highway through a densely built up urban area in Frederiksberg/ Copenhagen
with five to six storey apartment buildings. Transparent noise barriers have been used in combina-tion
with façade insulation.
6.2 Noise action plan
In spring 2009, the Danish Road Directorate published a proposal for a new noise ac-tion
plan for the existing state road network [ 1]. The purpose of the plan is to rank/ rate
initiatives that are planned to reduce road traffic noise along the state road network,
where the noise is considered unacceptable. Another purpose to rank/ rate noise initia-tives
in relation to planned maintenance of the road network.
New noise mapping using the ( new) LDEN indicator has been performed along 950 km
( 694 miles) of the 3,800 km ( 2,375 miles) state road network where the traffic is
higher than 16,000. A total of 58,277 dwellings are exposed to more than the guideline
of 58 dB ( see Table 6.2). Of these, nearly 4,400 are heavily exposed to noise higher
than 68 dB.
Table 6.2. Number of dwellings exposed to road noise ( L DEN ) along state roads with more than
16000 vehicles daily [ 1] at a height of 1.5 m ( 5 feet).
58 – 63 dB 63 - 68 dB 68 – 73 dB > 73 dB Total
Number of dwellings 39,216 14,660 2,984 1,417 58,277
Noise maps have been produced for all the municipalities with state roads passing
through with more than 16,000 vehicles daily. Figure 6.4 shows an example of one of
these noise maps for the municipality of Solrød.
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The noise mapping statistics for Solrød can be seen in Table 6.3. 1,388 dwellings are
exposed to more than 58 dB and 7 dwellings are exposed to over 68 dB. The sky blue
dots on the noise map represent highly exposed noise areas with more than five dwell-ings
where at least one dwelling is exposed to more than 68 dB. There are three such
areas along the highway through Solrød.
Figure 6.4. Noise map of the state highway through the municipality of Solrød [ 1].
Table 6.3. Statistics for the noise map of the state highway through the municipality of Solrød [ 1].
58 – 63 dB 63 - 68 dB 68 – 73 dB > 73 dB Total
Number of dwellings 898 483 7 0 1,388
The five year goal of the noise action plan is to reduce the noise annoyance for as
many dwellings as possible along the highway sections with the highest noise levels.
In the “ Green Transport Policy” from the Danish government in 2009, a budget of 400
mill. DKK (€ 54 mill. or USD 72.7 mill.) has been allocated for noise abatement in the
period from 2009 to 2014. The actual resources for noise abatement will be set aside
in the yearly national budgets. The first priority is to focus on dwellings exposed to
more than 68 dB and to get noise reduction at as many dwellings as possible for the
invested money. The second priority is to use noise barriers at road sections where the
most cost effective solutions can be reached. The third priority is to use façade insula-tion
along sections where it is not physically possible to use noise barriers and where
the solution is cost effective.
In relation to the ongoing maintenance of roads, another goal of the noise action plan
[ 29] is that the Danish Road Directorate will use noise reducing pavements wherever
pavements need to be renewed.
Existing noise barrier
Noise over 58 dB
Noise over 68 dB
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This goal will be applied at road sections where the noise exposure is over the 58 dB
guideline and the road passes through large residential areas.
6.3 System for tendering noise reducing pavements
In order to facilitate the use of noise reducing pavements, a system for tendering such
pavements has been developed in Denmark. In 2006, Danish road authorities in con-junction
with pavement industry and consultants worked out a system for the specifi-cation
and documentation of noise reducing asphalt pavement [ 30], the SRS- system,
SRS being the acronym for the Danish wording of Noise Reducing Surfacing. The
system is based on the Close Proximity Method ( CPX) [ 31] similar to the On Board
Sound Intensity ( OBSI) method [ 32] commonly used in California and USA for noise
measurements. In order to ensure reliability and transparency, it allows various inde-pendent
providers of CPX measurements to offer their service as long as they partici-pate
in an annual field calibration of equipment.
Figure 6.5. The CPX- trailer “ deciBellA” operated by the Danish Road Directorate/ Danish Road Insti-tute.
The system encompasses:
• A guide to the use of asphalt surfacing in traffic noise abatement.
• A system for the documentation and declaration in classes of the noise reduction of
the asphalt surfacing.
• Three classes A, B & C, where class A surfacings exhibit the highest noise reduc-ing
effect and class B & C exhibit lower noise reducing effects as compared to
regular dense graded asphalt surfacings at eight years of age.
• Reference values of the noise emission as determined by the CPX method.
• A description of the CPX method including the definition of method variables and
requirements on supplementary calibration of the measuring device.
• A paradigm for the contracting and preparation of tender documents.
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This is the first Danish attempt to provide a process for contracting noise reducing as-phalt
surfacings. It has limitations and several subjects need addressing. In particular,
there is a need for better knowledge on the accuracy of CPX measurement, and for the
development of appropriate acceptance criteria for contracting. The intention is for the
classification system to certify the noise reduction ability of road surfacings including
new products as well as to improve the ability of the local road administrations ( which
typically lack expertise in noise considerations) to purchase proven solutions fit for
use.
A contractor who wants to declare a SRS ( Noise Reducing Surface) must work out a
declaration form. In this form the contractor declares the actual noise class and pre-sents
the documentation achieved during CPX measurements on a trial section. The
contractor must build a test section of at least 100 m length. The CPX- trailer must run
over the trial section at the appropriate reference speed while recording the noise lev-els
with its two standard reference tires.
The system to declare the noise reducing ability enables the contractor to produce
documentation of the noise reduction of a specific SRS by comparing measured values
with a national reference value. The reduction in noise emission ( compared to the ref-erence)
is used by the contractor in the declaration of the SRS in a specific noise class.
The first generation system describes three noise classes – A, B, and C.
The reference values were derived as pass- by noise levels [ 33] calculated for reference
conditions using the Danish noise emission data of the Nordic prediction method for
road traffic noise, Nord2000 [ 26]. Using data between vehicle pass- by noise levels and
CPX noise levels, the Nord2000 pass- by noise levels were transformed to their corre-sponding
CPXDK values, which are used in the first generation system.
When declaring the noise reduction of an asphalt surfacing ( by comparison to the ref-erence
used in Denmark), one of the following noise classes A, B, or C should be
used.
Table 6.4. Noise classes in the Danish “ SRS” ( Noise Reducing Surface) system for noise labeling of
asphalt pavements [ 30].
Noise class Description Noise reduction in dB
A Very good noise reduction x > 7.0
B Good noise reduction 5.0 < x < 7.0
C Noise reduction 3.0 < x < 5.0
The Danish SRS- system is a voluntary road standard for contracting of noise reducing
pavements. In the contract for a specific job, the voluntary standards become legally
binding. However, at present the system is in an experimental phase with no legal
ramifications if the pavement fails to fulfill the noise performance requirements.
45
Figure 6.6. When the pavement on an existing highway has to be replaced, the road administra-tion
might consider using a new noise reducing pavement type. Here noise reducing two- layer po-rous
asphalt is applied on a highway in a densely built up area in the municipality of Copenhagen.
6.4 Other measures of noise abatement
The following represents different kind of measures of noise abatement that can be
applied along existing highways and other main roads.
Figure 6.7. Earth embankment with a path on the top designed to fit into the urban landscape
along a highway. Earth embankments can be made of surplus soil from road or housing construc-tion
projects in the region where a plan for the earth embankment is made and over a period of
many years, dirt is delivered to the site before the embankment is finished. It is important to have a
plan for the embankment in order to get a good final appearance in the visual environment.
46
Figure 6.8. Glass covering has been mounted as noise insulation for bedrooms and living rooms
at the façade of a multi- storey apartment building along a highway in Copenhagen, Denmark.
Cleaner air from the backside of the building is used for ventilation between the glass covering
and the existing windows. The noise abatement was financed as a part of an overall renewal of
the building.
Figure 6.9. Noise reducing window constructed as a “ noise shutter” that makes it possible to open
the window. Placed in front of bedrooms and living rooms facing the highway ( photo Allan Jensen,
Rambøll).
47
Figure 6.10. Close up of “ noise shutter” window where the extra noise insulating glass layer can
be pulled to the right side in order to be able to open the “ original window” ( photo Allan Jensen,
Rambøll).
Figure 6.11. Speed monitoring is normally used as a measure to improve traffic safety. If it has an
effect on reducing the actual speed it can also have a noise reducing effect [ 10].
48
Figure 6.12. Reducing the speed where a highway passes noise sensitive areas could reduce the
noise. A solution where the reduced speed limit is only effective in the evening and night period
could be considered in order to reduce noise annoyance when people are sleeping. This measure
is only effective at reducing noise only if the speed is actually reduced.
Another innovative idea that has been considered in Switzerland [ 29] is to build a con-crete
roof over the highway where it passes through noise sensitive and densely built-up
urban areas. Then the “ land” developed on top of the covered highway is sold as
construction sites for urban development like dwellings and offices. The revenue from
the ‘ new’ land sales might finance or partly finance the noise abatement project.
49
7. New housing along exiting highways
In the mid 1980 ´ s, noise was integrated in municipal land use planning in Denmark.
In the planning process of new residential areas a land use plan has to be developed
and approved by the local municipality. According to guidance from the Danish
Environmental Protection Agency, noise has to be taken into consideration in land
use planning and a guideline of noise at dwellings of 55 dB ( LAeq, 24h) and the recent
introduction of LDEN 58 dB has to be respected [ 23]. All urban land development
and construction of new housing has followed these noise guidelines for more than
25 years. The noise abatement measures have been enforced by the municipalities and
normally been paid for by the developer or contractor building new dwellings.
Figure 7.1. Earth embankment constructed at the same time as a new housing district to reduce
the noise from an existing road at the houses and the gardens at Kvistgård, Denmark.
The measures that normally have been used to fulfil the noise criteria are the follow-ing:
• Long distance between roads and new buildings.
• Construction of noise barriers in some cases as an integrated part of the building
design ( see Figure 7.3 and 7.5).
• Earth embankments that might be constructed of surplus material from the con-struction
site ( see Figure 7.1).
• Using secondary buildings like garages, carports, bicycle sheds, laundry buildings
etc as parts of noise barriers facing the road ( see Figure 7.2).
50
• In built- up urban areas, it is sometimes allowed to use the building itself as a noise
barrier in such a way that the building design has both a noisy and a silent side. In
such cases, noise insulation has to be applied to provide an indoor noise level not to
exceed 30 dB. The planning solution of the dwellings shall then be designed so the
windows of living rooms and bedrooms faces the quieter side of the building and
only ” secondary rooms” face the noisy side of the building ( see Figure 7.4).
Figure 7.2. A new district of row houses constructed along an existing highway. A common car-port
facility was constructed as a two storey high noise barrier.
Figure 7.3. New residential apartment building for elderly people where a transparent noise barrier
has been integrated in the building design.
51
Figure 7.4. New three and four storey apartment buildings constructed close to a highway with
high noise levels. At the façade facing the noise, the windows are small and highly noise insulated.
The apartments are planned so that secondary rooms like bathrooms, corridors, storage rooms, etc
are adjacent to the noisy façade. Bedrooms and living rooms are adjacent to the silent facade.
Figure 7.5. Brick noise barrier constructed as an integrated part of a new apartment building pro-ject.
52
53
8. References
[ 1] Sauer, Christian; Fryd, Jakob; Nøhr Michelsen, Lene. Noise action plan 2008-
2013. Action plan for larger state roads. ( Støjhandlingsplan 2008- 2013. Hand-lingsplan
for store statslige veje ( in Danish)). Danish Road Directorate. March
2009.
[ 2] Bendtsen, Hans. Noise Barrier Design. Danish and some European examples.
Danish Road Directorate/ Danish Road Institute. Report 174, 2009.
See: www. roadinstitute. dk.
[ 3] Bendtsen, Hans et. al. Knowledge Sharing on Noise Management and Abate-ment.
Report from CEDR, 2009. See: www. cedr. fr/ .
[ 4] Bendtsen, Hans; Kragh, Jørgen; Nielsen Erik. Use of Noise Reducing Pave-ments
- European Experience. Danish Road Directorate/ Danish Road Institute.
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[ 6] Proposal of a strategy to reduce road noise traffic ( Forslag til strategi for be-grænsning
af vejtrafikstøj ( in Danish)). Road Noise Group: Danish Environ-mental
Protection Agency, Ministry of Finance, Ministry of Transport, Ministry
of the Interior and Health, Ministry of Justice, Ministry of Economic and Busi-ness
Affairs, November 2003. See: www. mst. dk.
[ 7] Bendtsen, Hans; Michelsen, Lene Nøhr; Kristensen, Brian. New ideas for or-ganising
and financing urban noise abatement. Proceedings Forum Acusticum,
Budapest 2005.
[ 8] Technical Noise Supplement ( TeNS). A Technical Supplement To The Traffic
Noise Analysis Protocol. California Department of Transportation. Environ-mental
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Waste Management Office. October 1998.
[ 9] Traffic Noise Analysis Protocol. California Department of Transportation.
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[ 10] Bendtsen, Hans; Ellebjerg, Lars; Andersen, Bent. New methods for noise
abatement in municipalities – a catalogue of ideas ( Nye veje til støjbekæmpelse
i byer - et idékatalog ( in Danish). Danish Road Directorate, Report 295, 2004.
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[ 11] Ellebjerg, Lars. Cost- benefit analysis on noise- reducing pavements. Danish
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[ 12] Guide to preparing socio- economic assessment of consequences ( Vejledning
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54
[ 13] Manual for socio- economic analysis – applied method and practice in the field
of transport ( Manual for samfundsøkonomisk analyse – anvendt metode og
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( Nøgletalskatalog – til brug for samfundsøkonomiske analyser på transportom-rådet
( in Danish)), 2nd version, Danish Ministry of Transport, 2004. See:
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husprismetoden ( in Danish, English summary)), Environmental project no. 795,
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Teknisk og samfundsøkonomisk analyse ( in Danish)). External note no. 19,
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( Udbygning af Motorring 3. VVM- redegørelse – Miljøvurdering ( in Danish)).
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Motorring 3. VVM- redegørelse – Støj og vibrationer ( in Danish)). Danish Road
Directorate. Report 264, 2002. www. vd. dk.
[ 21] Route 18: Highway Riis- Ølholm- Vejle. EIA- statement - Environmental docu-ment
( Rute 18: Motorvej Riis- Ølholm- Vejle. VVM- redegørelse - Miljøvurder-ing
( in Danish)). Danish Road Directorate. Report 297, 2005. www. vd. dk.
[ 22] Directive 2002/ 49/ EC of 25 June 2002 of the European parliament and of the
council on the assessment and management of environmental noise, L 189/ 12
Official. Journal of the European Communities 18.7.2002.
[ 23] Noise from road traffic ( Støj fra veje ( in Danish)). Guideline from the Environ-mental
Protection Agency no. 4, 2007. www. mst. dk .
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( in Danish)). Danish Road Directorate. Report, 2007. www. vd. dk.
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[ 26] Kragh, Jørgen et. al. User’s Guide Nord2000 Road. Delta, SINTEF, SP and
VTT.
55
[ 27] The Nord2000 PC version can be downloaded from:
www. sintef. no/ Projectweb/ N2kR/ .
[ 28] Noise insulation of dwellings against road traffic noise. Project guide for the
administration of the Road Directorates system. ( Støjisolering af boliger med
trafikstøj. Projektvejledning for administration af vejdirektoratets tilskudsord-ning
( in Danish)). Danish Road Directorate, 2004. www. vd. dk.
[ 29] Bendtsen, Hans; Ellebjerg, Lars. Noise Reduction Efforts in Germany and Swit-zerland
– A Report of a Study Tour ( Støjbekæmpelse i Tyskland og Schweiz -
Rapport fra en studietur ( in Danish)). Note 73, 2000, Road Directorate.
[ 30] Kragh, Jørgen. Noise classification- asphalt pavement, Danish Road Insti-tute/
Road Directorate, Technical Note 61, 2007. www. roadinstitute. dk .
[ 31] ISO/ CD 11819- 2. ( Acoustics) – Method for Measuring the Influence of Road
Surfaces on Traffic Noise – Part 2: “ The close proximity method”, 2000- 12- 03.
[ 32] Further Development of the Sound Intensity Method of Measuring Tire Noise
Performance of In- Situ Pavements. Illingworth & Rodkin, Inc. Report prepared
for the California Department of Transportation January 4, 2006. See:
http:// www. i80. dot. ca. gov/ hq/ env/ noise/ pub/ 2_ Probe_ SI_ Report_ 04Jan06. pdf .
[ 33] ISO 11819- 1: 1997. " Acoustics – Measurement of the influence of road
surfaces on traffic noise – Part 1: Statistical Pass- by method." 1997.
[ 34] Bendtsen, Hans; Ellebjerg, Lars; Mikkelsen, Bo. Traffic Noise Annoyance.
A Survey in Aarhus, Odense and Randers. Report 5, 2002. Danish Transport
Research Institute, www. dtf. dk .
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