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Contract Number: SSPI-CT-2003-503549-IMAGINE
DeltaRailPO Box 8125
3503 RC Utrecht
The Netherlands
Telephone: +31 30 300 5100
telefax: + 31 30 3005 5150
email: [email protected]
IMAGINE
Improved Methods for the Assessment of theGeneric Impact of Noise in the Environment
Final Synthesis Report
Guidance on the Imagine methods
Project Co-ordinator: DeltaRail NL
Partners DeltaRail NL Boeing EDF LABEIN SP TUG
DeltaRail UK BUTE EMPA Leicester TML UGent
Anotec CSTB EUROCONTROL M+P TNO ULeeds
ARPAT DeBAKOM JRC MBBM TRL Volvo
Autostrade DGMR Kilde
Document identity: IMA10TR-06116-AEATNL10
Date: 2006-11-16
Level of confidentiality: public
Written by Date (YY-MM-DD) Reviewed by Date (YY-MM-DD)
Margreet Beuving, Brian
Hemsworth
2006-11-16 Steering Committee
The present publication only reflects th e author s views. The Community is not liable for any use that may be made of the inform ation contained herein.
www.imagin
e-project.org
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EXECUTIVE SUMMARY
This report gives an overview of the methods, guidelines and databases produced in the IMAGINE project.
The document is aimed to guide through the deliverables from the end users point of view and it gives
information on the IMAGINE deliverables at different levels, from management information to technical
guidance.
The groups of end users defined in the project are authorities, software developers, technicians, noise
mappers and operators. The report consists of 2 parts, each focusing on different end users.
Part I of this document gives a management overview with definitions, the background of the project and
links with the HARMONOISE project, advantages of the methods and subjects for further developments.
Part II describes the technical part of the projects, it gives flow diagrams and overviews of the contents of
the deliverables, both for the source methods (road, rail, industry and aircraft) and for the propagation and
the determination of the Lden by measurement and calculation.
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TABLE OF CONTENTS
Executive Summary ........................................................................................................................................................................................................... 2
Introduction........................................................................................................................................................................................................................ 6
PART I Management Overview ....................................................................................................................................................................................... 8
I.1 List of IMAGINE deliverables .........................................................................................................................................................................8
I.1.1.1 General ................................................................................................................................................................................................... 8
I.1.1.2 Road source............................................................................................................................................................................................ 8
I.1.1.3 Rail source.............................................................................................................................................................................................. 9
I.1.1.4 Industry .................................................................................................................................................................................................. 9
I.1.1.5 Aircraft ................................................................................................................................................................................................. 10
I.1.1.6 Mapping ............................................................................................................................................................................................... 10
I.1.1.7 Measurements and monitoring ............................................................................................................................................................ 11
I.2 Links between HARMONOISE and IMAGINE.............................................................................................................................................. 11
I.3 Advantages of the IMAGINE methods.......................................................................................................................................................... 13
I.4 Subjects for further development ................................................................................................................................................................... 16
PART II Technical description of the methods in global terms.................................................................................................................................. 19
II.1 Flow diagram................................................................................................................................................................................................. 19
II.2 Methodology...................................................................................................................................................................................................20
II.2.1 General ...................................................................................................................................................................................................... 20II.2.2 Road noise source ..................................................................................................................................................................................... 23
II.2.2.1 Introduction.......................................................................................................................................................................................... 23
II.2.2.2 How to determine the sound power level.................................. .......................................................................................................... 23
II.2.2.3 Road source input data......................................................................................................................................................................... 25
II.2.2.4 Methods of data collection................................................................................................................................................................... 26
II.2.2.5 Links with other IMAGINE Work Packages ...................................................................................................................................... 27
II.2.3 Road Traffic flow modelling ....................................................................................................................................................................27
II.2.3.1 Introduction.......................................................................................................................................................................................... 27
II.2.3.2 Road Traffic flow input data................................................................................................................................................................ 28
II.2.3.3 Methods of data collection................................................................................................................................................................... 29
II.2.3.4 Links between road traffic modelling and other IMAGINE Work Packages..................................................................................... 29
II.2.4 Rail noise source ....................................................................................................................................................................................... 31
II.2.4.1 Introduction.......................................................................................................................................................................................... 31
II.2.4.2 How to determine the sound power level.................................. .......................................................................................................... 32
II.2.4.3 Rail source input data........................................................................................................................................................................... 34
II.2.4.4 Methods of data collection/measurement methods ............................................................................................................................. 35
II.2.4.5 Links with other IMAGINE Work Packages ...................................................................................................................................... 36
II.2.5 Industrial noise.......................................................................................................................................................................................... 37
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II.2.5.1 Introduction.......................................................................................................................................................................................... 37
II.2.5.2 How to determine the sound power level.................................. .......................................................................................................... 37
II.2.5.3 The input and output.......................... .................................................................................................................................................. 38
II.2.5.4 Measurement methods......................... ................................................................................................................................................ 39
II.2.5.5 Links with other IMAGINE Work Packages ...................................................................................................................................... 40
II.2.6 Aircraft noise............................................................................................................................................................................................. 41II.2.6.1 Introduction.......................................................................................................................................................................................... 41
II.2.6.2 How to determine the sound power level.................................. .......................................................................................................... 41
II.2.6.3 The input and output.......................... .................................................................................................................................................. 42
II.2.6.4 Methods of data collection/measurement methods ............................................................................................................................. 44
II.2.6.5 Links with other IMAGINE Work Packages ...................................................................................................................................... 44
II.3 Propagation.................................................................................................................................................................................................... 45
II.3.1 The propagation method........................................................................................................................................................................... 46
II.3.2 Propagation paths...................................................................................................................................................................................... 48
II.3.3 Source segmentation................................................. ................................................................................................................................ 49
II.3.4 Geometrical data model ............................................................................................................................................................................ 49II.3.5 Input data and GIS .................................................................................................................................................................................... 50
II.4 Determination of long term Lden by calculation........................................................................................................................................... 52
II.4.1 Introduction............................................................................................................................................................................................... 52
II.4.2 Meteorological classes .............................................................................................................................................................................. 52
II.4.3 Classification variables ............................................................................................................................................................................. 52
II.4.4 Calculation of D/R .................................................................................................................................................................................... 53
II.4.5 Calculation of long term Lden .................................................................................................................................................................... 53
II.5 Determination of Lden and Lnight using measurements............................................................................................................................... 54
II.5.1 General ...................................................................................................................................................................................................... 54
II.5.2 Description of the method......................................................................................................................................................................... 54II.5.3 Input and output of the method................................................................................................................................................................. 55
II.5.4 Links with other IMAGINE Work Packages ........................................................................................................................................... 55
II.6 Factors affecting the quality and accuracy of end results ............................................................................................................................ 56
II.6.1 Road Noise Source.................................................................................................................................................................................... 56
II.6.2 Road Traffic Flow Modelling................................................................................................................................................................... 56
II.6.3 Rail Noise Source...................................................................................................................................................................................... 57
II.6.4 Industrial Noise..... .................................................................................................................................................................................... 57
II.6.5 Aircraft Noise............................................................................................................................................................................................ 57
II.6.6 Propagation ............................................................................................................................................................................................... 58
II.6.7 Measurement of Ldenand Lnight.................................................................................................................................................................. 58II.6.8 Mapping Specifications ............................................................................................................................................................................58
II.7 Databases....................................................................................................................................................................................................... 59
II.7.1 Road Noise Source.................................................................................................................................................................................... 59
II.7.2 Road Traffic Data......................................................................................................................................................................................59
II.7.3 Rail Noise Sources.................................................................................................................................................................... ................ 59
Data currently in the database ............................................................................................................................................................................ 62
II.7.4 Industrial Noise Sources ........................................................................................................................................................................... 63
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II.7.5 Aircraft Noise Source Database................................................................................................................................................................ 67
Proposeddatabase structure................................................................................................................................................................................... 68
II.8 References...................................................................................................................................................................................................... 70
Appendix I Presentations and papers during the project......................................................................................................................................... 76
Appendix II Quick scan of IMAGINE....................................................................................................................................................................... 80
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INTRODUCTION
In June 2002, the European Directive on the Assessment and Management of Environmental Noise
2002/49/EC, (abbreviated as END) was accepted and came into force. Under this Directive, member states
are obliged to produce strategic noise maps of major roads, railways, airports and large agglomerations by
30th June 2007. These noise maps shall express the environmental noise levels caused by the abovesources, in terms of the harmonised noise indicators Ldenand Lnight. From these, other statistics such as the
total number of residents exposed to certain noise levels shall be derived. This information shall then be
submitted to the European Commission and made public. The next step will be to draft Noise Action Plans,
the first of which will have to be produced by July 2008.
It has always been the intention of the Commission to establish common assessment methods for the
production of these noise maps but until such methods are made available, the END has defined interim
methods. These interim methods or a Member States national method, if it can be shown to be equivalent
to the interim method, will be used in at least the first round of mapping in 2007.
As a first step in developing a common method, the project HARMONOISE was initiated in August 2001.
This project was partly funded by the European Commission (DG Information Society and Technology)
under the 5th framework programme. Its main objective was to develop harmonised, accurate and reliable
methods for the assessment of environmental noise from roads and railways. In order to produce a model
that was capable of predicting the long term average Lden and Lnight the Harmonoise philosophy was to
separate source and propagation. It thus developed source models for road and rail and propagation
models for these sources that included the effect of distance, air absorption, ground effect, barrier diffraction
and meteorological variables such as wind and temperature gradient. Following validation of the
propagation model this project was completed in August 2004.
The IMAGINE project, which commenced in November 2003 as Strategic Targeted Research Project which
addresses Task 3 of the Scientific Support to Policies (SSP) Call under the 6th Framework Programme. The
project aimed to extend the Harmonoise source databases for road and rail and to use the Harmonoise
methodology to develop prediction methods for aircraft and industrial noise sources. This required the
setting up of industry and aircraft source models together with such modifications to the propagation models
as was necessary to account for high sources (aircraft), large sources (industry) and diffraction by vertical
barriers (industry).
The overall objective of both projects is therefore to provide a model which meets the requirements of a
common assessment method and which eventually can be adopted for use for strategic mapping as defined
by the Environmental Noise Directive.
The main technical objectives of Imagine are:
1. To provide practical guidelines for data management and information technology aspects of noisemapping (Work Package 1),
2. To provide guidelines and examples for an efficient link between traffic flow management on the one
hand and noise mapping and noise action planning on the other hand. (Work Package 2),
3. To provide guidelines and examples of how and when noise measurements can add to the credibility
and reliability of assessed noise levels (Work Package 3),
4. To provide a harmonised, accepted and reliable method for the assessment of environmental noise
levels from airports, which links well within the methods for noise propagation description developed in
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HARMONOISE and at the same time has a large acceptance in the field of future users and other
stakeholders (Work Package 4),
5. To provide default databases for the source description of road noise, i.e. vehicle category and road
surface type, for a typical fleet of European road traffic, and provide guidelines on how to deal with
situations deviating from the default value (Work Package 5),
6. To provide databases for the source description of rail noise, i.e. vehicle category and track type, for an
example sample of the European rail traffic fleet, as well as default data sets, and provide guidelines on
how to deal with situations deviating from the typical (Work Package 6),
7. To provide a harmonised, accepted and reliable method for the assessment of environmental noise
levels from industrial sites and plants, which links well within the methods for noise propagation
description developed in HARMONOISE, in combination with methods for source description by
measurements based on the existing set of standards and guidelines, together with a default database
for typical sound production for a limited but representative number of industrial activities (Work
Package 7),
8. To provide for acceptance and easy and quick implementation of the above deliverables and those from
the HARMONOISE projects, in order to allow a smooth and harmonised process of noise mapping and
noise action planning in all member states (Work Package 8).
The completed work is consistent with the Description of Work submitted at the commencement of the
project. This means that there are a number of issues that were not covered within the project. These were:
Standardisation of results
Extended validation (at an international level) of the methods
Development of test cases for software benchmarking
Development of commercial software.
It is appreciated that these are important issues that will need to be addressed before the IMAGINE method
can be considered as a candidate for the common assessment method and a number of Imagine partners
are discussing the next steps necessary in this acceptance process.
Book-mark to this document
This report consists of two parts. Part I is meant to give a quick overview for management purposes of the
project results, the background and future developments. The advantages of the IMAGINE methods are
outlined. Part II guides the reader through the technical results by descriptions of the methods per work
package and by cross references to the project deliverables. This part is aimed at end users needing to
understand the methods in global terms and to know the implications for practical use. Lists of required
parameters are given and implications for accuracy are briefly described.
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PART I MANAGEMENT OVERVIEW
I.1 List of IMAGINE deliverables
I.1.1.1 General
Deliverable D1 Imagine Website www.imagine-project.org
The project website contains all relevant information about the project, the latest news and research results,
the organisations and the partners involved in this project. The website has two parts, a public part and a
restricted part. The public part is presented in popular (not too technical) language. The restricted part of the
website is only accessible for members of the project. The website is subscribed to the most popular search
engines and is linked to sites such as national acoustic societies, universities, ministries, stakeholders,
related magazines and the site of the EC.
Deliverable D2 - IMAGINE State-of-the-Art, Report IMA10TR-040423-AEATNL32
This report describes the methods to determine Lden or similar measures, and possibilities for action
planning which were available at the start of the project. The conclusions were that there was no calculation
method available anywhere to determine Ldenand that all methods dealing with similar measures shared the
deficiency that they did not make a separation between the source and propagation model s. Besides the
existing methods did not take into account all relevant parameters needed to produce sufficiently accurate
noise maps. These conclusions served as a starting point for the IMAGINE project.
Thats a bit harsh to say! Weve been using NMPB for year and were legally engaged by the predicted
results! Id say Weaknesses and missing elements in existing methods were identified.
Deliverable D15 Final Synthesis Report, IMA10TR-06116-AEATNL10
This is the underlying report describing the main IMAGINE results and the use of the IMAGINE methods.
Is that the right word?
I.1.1.2 Road source
Deliverable D3 Assessment Programme for Parameters of the general European vehicle fleet,
Report IMA52TR-060111-MP10
This deliverable describes the road noise emission model and the data collection campaigns at the first
stage of the project. It represents the intermediate status of the model at that time.
Deliverable D11 - The noise emission model for European road traffic, Report IMA55TR-060821-
MP10
This report represents a noise emission model for road vehicles that accounts for the characteristics of
different vehicle types and for the variations of the vehicle population in different European regions. It
contains the road source noise model equations and correction factors. Furthermore, validation of the model
against roadside measurements is presented, and the coupling between traffic flow modelling and road
noise source modelling is addressed.
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Deliverable D7 Guidelines for the use of traffic models in noise mapping and noise action
planning, Report IMA02DR7-060531-TNO10
The purpose of this report is to assist authorities and consultants in using traffic models to produce road
traffic data for noise mapping and noise action planning. It provides information on how to improve a traffic
model for noise mapping and noise action planning. The subjects treated in the guidelines are speed,
acceleration, traffic composition, diurnal and long-time patterns, low flow roads, intersections and gradients.
There are separate guidelines for noise mapping for main roads and for agglomerations, and for
macroscopic and microscopic models. The guidelines recommend methods for the improvement of traffic
models and give indications of the complexity, accuracy and cost of implementing the method.
I.1.1.3 Rail source
Deliverable D12/D13 Rail noise database and manual for implementation, Report IMA6TR-
061015-AEATUK10_D12/13
The report D12/D13 Rail noise database and manual for implementation accompanies the delivered rail
noise source database. It describes the general philosophy that has been applied to quantifying thedisaggregated sub-sources and storing the data. It also includes guidance on measurement, instruction on
data import and export, a method for creating the rail traffic model, advice on addressing non-standard
situations, and a default dataset. This Deliverable is a combination of the originally planned Source
database and Guidelines for typical situations.
My dictionary doesnt know these words
I.1.1.4 Industry
Deliverable D6 Description of the Source Database - WP7: Industrial Noise,Report IMA07TR-
050418-DGMR01
An extensive database with a large number of industrial noise sources and their characteristic noise
emissions has been produced. For each source or industry type a typical example for the sound power
levels given for representative modes of operation, taking other aspects such as quality in terms of low
noise emissions etc. into account. The database is a powerful and convenient tool for the potential end user
that needs sound emission data for industrial noise sources for noise mapping purposes. However, the
database will have to be used with caution because there are a number of risks associated with its
application to noise mapping that are not evident - especially to the inexperienced user.
End users that needs = Grammatical correction proposed by Windows?
Some commas would do a great job in long phrases
Deliverable D14 Guidelines for producing strategic noise maps on industrial sources, Report
IMAWP7D14-060811-DGMR03
This deliverable describes the work carried out for integrating industrial noise sources into the
HARMONOISE/IMAGINE model including modifications required to the propagation model for it to be
suitable for industrial source/propagation/receiver situations. Guidelines are given on how to make strategic
noise maps for industrial sources.
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I.1.1.5 Aircraft
Deliverable D9 - Reference and Engineering Models for Aircraft Noise Sources, Report IMA4DR-
061017-EEC-09
Deliverable D9, ref. [37], is in three volumes of which volume 3 consists of appendices. Volume 1 deals with
the propagation models:
Modifications required to the reference model in order to take high-level sources into account - thedefinition of a hybrid model using both a two-ray method, for higher altitude sources, and the
original parabolic equation (PE) method for determining propagation
How the atmospheric conditions encountered in the vertical plane are classified and how wind,temperature and humidity profiles may be created
The effects of atmospheric absorption
The adaptations required to enable the Engineering model to be applied to aircraft noise sources.
Volume 2 treats the validation work performed using a series of flight measurement trials performed at
Ocaa, near Madrid, in Spain in September 2006. Some of the flight measurements were de-propagated
in order to produce a full noise source description of the test aircraft. The propagation models were then
applied to this source description and the results analysed.
Deliverable D10 Default aircraft source description and methods to assess source data, Report
IMA4DR-061204-Empa-10
D10 provides information on how to generate sound source data and how to store it in a database, including
a description of the procedures to measure and to process data for the source emission model, how to infer
source emission data from existing NPD information, how to store, exchange and use source data,
proposing a data tables and a data base structure.
Oops? Theres something wrong with the structure of that sentence. But I cant find out. You might try to
split it in 2 or 3 shorter ones.
Were missing the main improvement here: spectral sound powers and directivity functions.
I.1.1.6 Mapping
Deliverable D4 Specifications for GIS-Noise databases , Report IMA01-TR060526-CSTB05
D4 deals with the geometrical input for building a noise model. It starts from the best possible practice in
view of the state of the art laid down by the Harmonoise and Imagine projects and works down toward its
consequences for the future end-users.
Deliverable D8 Guidelines and good practice on strategic noise mapping, Report IMA01-
TR22112006-ARPAT12.doc
Deliverable D8 mainly reflects the point of view of noise engineers confronted to the problem of carrying out
noise mapping project conforming to the specifications of the European Noise Directive. It deals with
aspects of noise mapping such as data collection and preparation, the estimation of exposed populations,
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the assessment of quality of noise maps and innovative technologies that may help in collection cheaper
and/or more accurate input data.
In combination, deliverables D4 and D8 aim to provide some answers to questions that were put forward at
the beginning of the project, like:
What do I need to make a noise map?
How to produce a good quality noise model?
Where can I get what I need?
How to obtain descent data at a reasonable cost and effort?
What will change after the introduction of the harmonised prediction methods?
Layout
I.1.1.7 Measurements and monitoring
Deliverable D5 Determination of Lden and Lnight using measurements, Report IMA32TR-040510-
SP10
This deliverable describes the method to determine Ldenand Lnightusing measurements, and is a standalone
document written in the format of an ISO-standard. This means that a potential user only needs this
document to carry out this type of measurements. For an ISO member body that wants to standardise the
procedure the document can be submitted as a first draft when voting for a new work item.
UK English turned on as default language on my computer
I.2 Links between HARMONOISE and IMAGINE
In the predecessor of IMAGINE, the HARMONOISE Project, methods for road and railway noise and forpropagation have been developed and validated. In IMAGINE the HARMONOISE methods have been
further developed and extended for aircraft and industry. This means that the HARMONOISE deliverables
do not always contain the latest versions of the methods. In general the IMAGINE deliverables are the most
up-to-date descriptions of the methods. The next table gives a short overview of the results of both projects.
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Sourcedescription
Source data Propagationmodel
Mapping methods Action planning
Road sources Developed inHARMONOISE andIMAGINE
Source datacollected inIMAGINE. Traffic
flow modelsdescribed inIMAGINE
Source descriptionand traffic flowmodelling allow
analysis at thesource
Rail sources Developed inHARMONOISE andIMAGINE
Source datacollected inIMAGINE.Measurementmethods developedin HARMONOISEand IMAGINE
Developed in
HARMONOISE andIMAGINE
Source descriptionand traffic flowmodelling allowanalysis at thesource
Industrialsources
Overview ofmeasurementmethods inIMAGINE
Source database(SourcedB)developed inIMAGINE
Adapted inIMAGINE for lateraldiffraction
Meteo classes andmapping guidelinesin IMAGINE
Categorisation ofdifferent industrialactivities allowaction planning
Aircraftsources
Developed inIMAGINE, based
on separationtechnique betweensource andpropagation
Methods developedin IMAGINE to
deduce data fromexisting models
Adapted inIMAGINE for high
sources
Meteo classes andmapping guidelines
in IMAGINE
Source descriptionand traffic flow
modelling allowanalysis at thesource
1) Show that propagation and mapping methods are common to all sources. This is one of the advantages
of IMAGINE. As presented, once has the impression that there are different propagation and mapping
methods for each source
2) IMAGINE did not develop mapping guidelines for aircraft. These are described in sufficient detail in
ECAC.Doc29
3) Action planning: I CANNOT AGREE WITH THIS PRESENTATION.. As presented one has the
impression that action planning solely relies on the source & traffic. I agree that IMAGINE provides a better
source description and therefore makes it possible to take into account these actions in a more appropriate
and accurate way then before.
It is not politically correct. Today 99% of EU research effort on noise reduction goes to the polluters, i.e. to
the transport industry. Do they aim for 100% in the near future?
On the other hand 99% of the efforts and cost for making the noise maps and setting up the action plans is
spent by local authorities. These are the people in direct contact with the citizens complaining about noise.
These are also the people that were difficult to convince for carrying out the noise maps in 2007. How will
we convince them to use Imagine/Harmonoise in 2007? What are the benefits for these people?
Those whove never made a noise map in their whole life better put their believes aside and listen to those
who have 20 years of experience in the field of making noise maps, action planning and presenting results
to the citizens.
The HARMONOISE propagation method has been extended in IMAGINE for practical use and for the
calculation of Ldenat the receiver. The points which have been added and improved are:
Use of external GIS data in the noise modeling, ref. [4]
Adaptation of the propagation model to industrial noise sources, ref [75]
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Adaptation of the propagation model to aircraft noise, ref [37]
Estimation of populations exposed to noise, ref [7]
Determination of Lden and Lnight as long term averaged quantities, ref. [78]
Pre-processing of meteorological data for the calculation of Lden and Lnight, ref [78]
Avoid the term meteorological classes when talking about propagation classes I think this better
describes what we did.
In the HARMONOISE project it was shown how noise levels are influenced by meteorological conditions
such as wind speed, wind direction and thermal inversion effects. For the determination of long term
averaged noise levels by means of measurement or calculations, short time levels, valid under specific
meteorological conditions, must be weighted according to their frequency of occurrence. The step-by-step
method to define the occurrence of meteorological conditions is an output of IMAGINE.
Either meteorological conditions or propagation classes. Dont mix.
I.3 Advantages of the IMAGINE methods
Road source method
The road noise source method represents the noise emission of the average European road vehicle. It is
more suitable for noise mapping purposes than currently used methods because:
it is based on extensive and recent measurement sets from the most important European regions,and therefore is truly representative of the European average,
Recent is a good point Interim NMPB is based on Guide du Bruit measurements in the late 70
heavy duty vehicles (trucks) and powered two-wheelers (mopeds, motorcycles) have receivedspecial attention and are now supported with extensive measurement data;
it provides correction factors to adapt for local variations in road surfaces and vehicle fleet.
Traffic Modelling
Traffic models are needed becausein most cases it will be impossible to construct a noise map without any
form of traffic modelling becausethere is not enough measured traffic data. Also, in noise action planning, a
traffic model is needed to determine the expected effects of measures.
Simplify. Traffic models are needed whenever there is not enough measured traffic data available.
With the guidelines given in Deliverable D7 (Guidelines for the use of traffic models in noise mapping and
noise action planning), more accurate traffic flow data can be produced when using a traffic model. The
purpose of the report is to assist authorities and consultants in using traffic models to produce road traffic
data for noise mapping and noise action planning. Separate guidelines are given for noise mapping and
noise action planning. For noise mapping, a further distinction is made between noise mapping for main
roads and agglomerations, and between macroscopic and microscopic traffic models.
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In addition to the guidelines, the technical report of task 2.4 Collection Methods for Additional Data[16]
provides guidance on how to collect traffic data to improve traffic models or their output, or to measure the
traffic flow data needed for making a noise map.
Railway source method
In the Harmonoise/IMAGINE rail model the combined roughness of the wheels and the rails is a key
parameter for rolling noise. The inclusion of the combined roughness leads to a major improvement in
modelling accuracy, especially because local track roughness can cause rolling noise to vary over a range
of up to 20 dB. At present, most national rail noise models include overall rolling noise data (i.e. vehicle +
track contributions combined) that have been acquired from pass-by measurements on track that is not
excessively rough or corrugated.
Your decision to call it Harmonoise/Imagine model. I can agree on Harmonoise methods and Imagine
data but the model is a combination of both.
In the Harmonoise/IMAGINE model, rolling noise is split into the vehicle and track contribution. In addition,the rail model takes into account all other potential noise sources, such as traction elements (exhaust, fans,
compressors), braking noise (including brake squeal), curve squeal and aerodynamic noise. The level of
detail of these extra sources is significantly greater than is the case with other available mapping models.
This complete separation allows a detailed apportionment of the rolling noise sub-sources and it allows an
evaluation of the effects of noise mitigation applied to sub-sources. This is a valuable tool in Action
Planning, and is also useful for identifying whether vehicles or track are the prime emitters of noise, helping
with such considerations as track access charging or determining responsibility when levels are exceeded.
The source term database and associated procedures for acquiring and storing data provide a standardised
and efficient method both for accessing appropriate data and for adding new data. In its delivered form it
holds example data from France, the Netherlands, Sweden, Hungary and the UK, representing a broad
range of generations of rolling stock, configurations and operating speeds. The database also provides
default data. Noise mappers who wish to model vehicle types that are not already within the database are
provided with guidance on how to acquire the data. Such a comprehensive pan-European rail source
database has not been available previously and represents a significant improvement in knowledge as well
as in the harmonisation of rail noise modelling.
Industry
If industry is located next to housing development, noise can become a problem. Unlike roads, where a
large number of different vehicles pass by, the noise may be the product of just a few sources. Although
these sources may be common to a large variety of industries, their usage (operating speed-maintenancelevel-operating hours) may differ greatly from company to company. So it is often not enough to have a
general knowledge of the source, it is better to measure the source.
Deliverable D14 [75] gives a very large number of measurement possibilities, in order to obtain the sound
power levels of machine and areas. If no measurement data are available, the source database SourcedB
[72] can be used containing a large variety of noise sources, based on measurements or formulae. This
database which contains more than 1500 entries is available from the DGMR website and has already been
downloaded more than 125 times.
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The noise propagation part is superior to the interim methods because of the possibilities of including
meteorological conditions. The method proved to be valid for many meteorological situations. A method is
proposed in ref. [78] for calculating the Ldenand Lnight, based on the statistics over a year.
Ai rcraft
Currently used aircraft noise models, including the Interim model, are based on the "integrated" modelling
guideline defined in European Civil Aviation Conference (ECAC) Doc. 29 [40]. These models have allnoise
sources (engine and airframe) and propagation combined into a set of "Noise-Power-Distance" (NPD)
curves for each of the two phases of flight - approach and departure. This method does not allow for taking
into account:
- realistic directivity of the aircraft source under various operating conditions
- temperature gradients and other meteorological effects;
- ground characteristics and shielding by relief.
The IMAGINE model described in ref. [37]and ref. [38] is a source-propagation model that takes all these
factors into account, enabling much more accurate analysis to be undertaken.
Work performed in IMAGINE has demonstrated the creation of example source data either by measurement
or by reverse-engineering of NPD data. For the noise calculations, the aircraft is modelled as a point source
with three-dimensional spectral directivity to account for the different contributions from individual sound
sources like fan, engine, jet and aerodynamic effects.
Two angles = a three-dimensional direction
Propagation Method
The interim propagation method and most national propagation methods are derived from the ISO 9613-2standard. This standard provides an empirical model to estimate the propagation effects in a very simplified
situation (i.e. a flat terrain with a single screen). When applied to more complex situations, the real geometry
has to be matched to this simplified description. How to do this is not part of the ISO standard. Even
though some national methods provide rules for the determination of the geometrical parameters, a large
degree of freedom is left to the software developers. As a consequence, different implementations based on
these common standards often lead to significantly different results, even in moderately complex situations,
and differences up to 5 or even 10 dB(A) are not unusual.
With HARMONOISE/IMAGINE methods a harmonised approach is possible through the following steps:
1. The HARMONOISE model relies on explicit geometrical modelling of propagation paths; i.e. it is the
complex geometry of the paths that is used as the input to the model. Because the softwaredevelopers do not need to interpret the geometrical data, this will clearly result in higher
reproducibility of the results.
2. The IMAGINE project provides a complete and explicit set of specifications for the geometrical
model (i.e. the data) on which the HARMONOISE methods (i.e. the algorithms) operate. Such
specifications define the end-user requirements for the collection of data and for the construction of
the geometrical model. As much as possible, these requirements are expressed in quantitative
terms.
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3. Sensitivity analysis of the HARMONOISE/IMAGINE method provides explicit links between the
accuracy and the level of detail of input data and the expected accuracy of the results. This also
allows for objective rank ordering of the data items to be collected.
As part of the common models and methods as prescribed by the END, the IMAGINEproject also looked into
common methods for the estimation of populations exposed to noise ref. [4].
Measurement of Ldenand Lnight
There is no interim method for the measurement of Ldennor is there any international or national method
addressing all the relevant parameter related problems resulting from the use of the HARMONOISEsource
and meteorological models. Thus the measurement method developed within IMAGINE introduces many
new features compared to available methods. The most important new features are
measurements are classified into meteorological classes. The measurement method is harmonisedwith the IMAGINE calculation methods for road, rail, aircraft and industry noise.
stratification of measurement according to meteorological conditions results in higher accuracy
measurement uncertainty is dealt with in compliance with the guidelines given in ISO GUM
the method is general and can be adapted both to industrial noise and road, rail and air traffic
both short term and long term measurements are dealt with
correction of measured values to be representative for yearly averages is dealt with
the method is flexible, different measurement efforts will yield different measurement uncertainties.
I.4 Subjects for further development
Road Traffic Noise Mapping
Although the predicted noise levels represent the European average, and some variations between
countries and regions are accounted for, reliable data from different countries showed differences in the
lower frequency range that could not be explained. Some ideas about the origin of these differences
described in ref. [52] should receive more attention.
Furthermore, the corrections for vehicle acceleration could be improved. Gathering data for this correction is
difficult, especially for heavy duty vehicles. A more dedicated measurement campaign would definitely
improve the results.
Note to Gijs-Jan: do measurements uphill, youll combine constant speed and constant acceleration!
Many techniques and data have been collected and investigated that are similar to the work done in the field
of traffic air pollution. A combined approach is more efficient and beneficial for both fields, and for the end
users, and should definitely receive attention in the future.
Traffic Modelling
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No specific road traffic model is recommended to produce traffic flow data. In principle, many different types
of (commercially available) traffic models can produce the data required for the road noise source model.
Deliverable 7 Guidelines for the use of traffic models in noise mapping and noise action planning can
assist in choosing the most appropriate model in the context of noise mapping and noise action planning. It
also gives guidance on how to improve traffic models in the context of noise mapping and noise action
planning. It is up to the users of the traffic model to use a suitable traffic model, provide good quality input tothe model and be aware of the limitations of the model and its output.
Railway Noise Mapping
The rail noise database framework has been written in Access and is linked with a standardised input
spreadsheet so that data is automatically transferred to the database. The algorithm for converting sound
pressure level, as stored within the database, to sound power level as required for assembling the traffic
model, is presented, but this process is not automated. Similarly, the algorithms for building the traffic model
are available, but this process is also not automated. Therefore these two elements require attention during
the implementation of IMAGINE. A tool to link the database with GIS software, enabling rail source data tobe extracted into the GIS environment automatically, would be desirable, possibly by the creation of an
appropriate .dll.
What is that supposed to mean? Extract into, isnt that a contradiction? I can extract available data from
GIS or I can put new data into a GIS data set. Of course the best way to go is: to interface the database
with noise mapping software. E ither the software directly addresses the Access database not a problem,
but the software developers need to re-programming the calculations of Lw from Lp and/or roughness data.
Either someone provides an API (an Application Programming Interface) to a library module (might be a
DLL) that does the job of extracting the data from the database and returning Lw to the application.
The example data included within the database has been designed to cover the full range of typical stock
that operates across Europe. This allows noise modellers to identify examples that are identical or similar tothe specific stock at locations of interest to them. There is also the option of using the default data provided
within the database.
However, it will always be necessary to add new data to the database, both where new, relevant, examples
are needed for specific locations and networks, and where new trains come into service. The database has
been designed specifically to allow this to happen efficiently in the future. The user interface is clear and
straightforward, but it is necessary for the database to be administered and maintained by an expert central
administrator who will be able to judge the appropriateness of the available data and ensure that the data
has been imported correctly. The administrator will also be able to manage the release of data to modellers,
including the provision of advice on which datasets will be of use. This system of administration and
maintenance requires setting up before the IMAGINE model can be fully implemented.
Industrial noise Mapping
Limitations in the model are the lack of validation within a densely built-up area.
Ai rcraft Noise Mapping
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The major problem facing the Imagine model is the availability of data. In IMAGINE an example set of data
has been reverse-engineered from NPD curves. These data are fairly approximate and incomplete. A
complete set of data needs to be supplied for each aircraft that will be needed in the database.
This is most easily done by the manufacturers themselves. These manufacturers are, however, very reticent
to supply what they consider confidential intellectual property. If the political will can be found to encourage
them to supply these data, there will be a significant financial price to pay.
Another method of producing these data is to perform a series of measurement campaigns, measuring and
converting data from a number of fly-pasts of each aircraft. This will be extremely costly.
Propagation models
At present the propagation model is only available as an executable dll-file and as a number of reports. It
still remains to describe the model systematically including all algorithms used in order to make it possible
for software writers to make their own optimizations of the algorithms used.
It turned out that most available software packages already include most features of the extended three-dimensional modelling required for the new methods. However their different approaches can easily lead to
5 or 10 dB(A) differences in complex situations, so harmonisation and/or standardisation is required after
the IMAGINE project in order to promote common modelling techniques for 3D geometry, to guarantee the
reproducibility of propagation path detection methods or to increase the interoperability of software.
Geographical Information Systems are already largely used to collect, store and manipulate the input data
for noise mapping. One of the main challenges when using currently available data with the new prediction
methods is to handle inaccurate, incomplete or missing data. Modelling solutions for these situations are
provided in ref. [3] and ref. [4], in such a way that the new methods can in principle be used with todays
data. In order to take advantage of the increased accuracy and the extended modelling capacities of the
new methods however, new data must be collected or existing data refined to higher levels of detail.
Measurement of Lden and Lnight
As the IMAGINE method for the measurement of Lden and Lnight introduces many new features it would be
desirable to evaluate it after having been in use for a few years. It would then be possible to learn from the
experiences and improve it further. It would be desirable to establish more default values for some
uncertainty components and to get further experience from the combination of measurements and
calculations.
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PART II TECHNICAL DESCRIPTION OF THE METHODS IN GLOBAL
TERMS
II.1 Flow diagram
Propagation
Basic source
properties
Databases
Measurement
methods
Traffic flow P2P model
Meteorological
conditions
Geometry Surroundings
Buildings
Lden
Propagation classes
Source Propagation
Basic source
properties
Databases
Measurement
methods
Traffic flow P2P model
Meteorological
conditions
Geometry Surroundings
Buildings
Lden
Propagation classes
Source
Ive seen nicer versions of this picture in other reports
The global structure of the HARMONOISE and IMAGINE methods is given in the schematic overview
above. A clear separation is made in the model between the source descriptions for road, rail, industry and
aircraft sources, and propagation to the receiver. The result of the source models is a sound power level per
source type for each source height relevant to that source, together with a certain directivity. The source
methodologies are described in chapter II.2.
The P2P model describes the sound propagation via a predefined path from one source point to one
receiver point, and forms the basis of the propagation model. The selection of the P2P paths is made in thepropagation method itself. The model also describes how meteorological conditions influence the shape of
one propagation path. Chapter II.3 describes the P2P method and the use of GIS.
Weve discussed this in an e-mail discussion and come up with an acceptable text. Please copy that text
instead of this non-sense
The result of the propagation model is an Leqat a specific receiver point for a given propagation class (the
meteorological influence on the propagation paths is divided into 4 different propagation classes). The total
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Leq from a source is the summation of the contributions of the different sub sources (located at different
heights) via their respective propagation paths.
The Ldenand Lnightvalues are calculated from the Leqvalues by determining the occurrence of the different
propagation classes within the time period of assessment, and summing the relative contributions of each
class. The determination of long term Lden(Lnight) by calculation and the propagation classes are described in
chapter II.4, the measurement of long term Lden(Lnight) is described in chapter II.5.
Chapters II.6 and II.7 describe the quality of the end results and the databases.
II.2Methodology
General
In the following diagram the steps of the mapping process for each source type are outlined.
Site measurements,then calculate SWL(1/3 oct bands, persource,
Define locations ofsource lines with endpoints in more detail
Identify roads anddefine road sourcelines with end points
Define locations ofsource lines with endpoints in more detail
Identify road sources,vehicle classes
Define operatingconditions per unit oftime (day, evening,night), #per hour,speed, acceleration,braking, etc.
Calculate SWL (1/3oct bands, sourceheight, per m ofsource line
Correction factors,directivity, regionalvariations, roadsurface type, wintertyres, etc.
Sum of SWLs persource height
Road
Identify railways anddefine railway sourcelines with end points
Identify rail vehicletype, track types,traction noise, rollingnoise, aerodynamicnoise
Define operatingconditions per unit oftime, (day, evening,night), # per hour,track roughness,speed, acceleration,braking, etc.
Correction factors,directivity, curves,oints, bridges, etc.
Calculate SWL (1/3oct bands, sourceheight, per m ofsource line,
Sum of SWLs persource height
Rail
Define sourcelocations
Identify source types(point, line, area, orvolume source),source classes, planttypes
Define operatingconditions, #per unitof time (and day,evening, night),working hours,
Correction factors,directivity
Industry
Identify airport runway usageand ground track
Identify aircraft types andengines
Determine number of flights ofeach aircraft type on eachflight path, day, evening, night
Convert each flight path intoshort segments. Calculate thetime t the aircraft is within
this segment. Calculate theposition within this segment toplace the point sourcerepresenting the aircraft.
For a specific receiver point,determine the emission angles(including bank angle) and
determine from the soundsource model the sound power
spectrum for the appropriate
angles, thrust and operation(landing/departure)
Describe flight profiles (height,speed, engine thrustas afunction of flown distance) foreach aircraft type and forclasses of take-off weight.
Aircraft
Define locations andsizes/heights ofsources in more detail
For curved flight, calculate thebank angle of the aircraft (=lateral inclination)
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Too complicate to correct this incomprehensible schema!
Removed per hour for Calculate SWL. Calculation of Lwon an hourly basis is NOT mandatory. it might beuseful for road traffic because flow and speed depend on the hour of the day. But it is incompatible with therecommended methods for aircraft and industry.
Is SWL an official abbreviation???? Like SPL or SEL? Thats what the AMERICANS use for the ISO
symbols Lpand LE ! If possible write Lw for sound power level.
Sum of SWL ???? Sum over what? Over sub-sources? Over vehicle classes? Over hours of the day?Over day-evening-night???
Basic steps are:
1) pre-processing: identify infrastructure, identify vehicle / source types, collect data on operatingconditions. This is common to all sources.
2) Specific to aircraft: flight path depends on ground track + aircraft/engine type + ambient temperature +take-off mass; this requires the use of aircraft performance data.
3) source segmentation, assume Lw is constant over the segment
4) calculate Lw by summing similar sub-sources (i.e. at the same height) for all vehicle classes ; there areno sub-sources for aircraft (unless one considers flight track dispersion as some kind of sub-sources).
5) determine the directivity in the direction of the receiver, for aircraft: take into account bank angle.
The result is a sound power level (SWL) in 1/3 octave bands per source height or per source, per hour for
the day, evening or night period. The methods for gathering data and calculating the SWL are described in
the following sections. The sound power level feeds into the propagation calculations that are described in
section II.3 of this report.
Definitions used in the scheme
Source lines tracks, roads, flight paths
Source segments parts of source lines on which Lwis assumed constant or almost constant.
Source locations location of industrial sources (point sources, line sources, area sources or volume
sources)
Source types train vehicle types, track types, industrial sources, aircraft types in combination with engine
types
Operating conditions numbers per hour (yearly average), speeds, acceleration, braking, working hours
Unit of time period of time during which the operating conditions are considered constant, normally this will
be an hour
Correction factors correction for road type, directivity of the source, curves, bridges, road surface types,
winter tyres, etc.
Aircraft noise calculation
The overall calculation of aircraft noise consists of several loops: First, the sound level at the receiver is
calculated for a specific position of the aircraft as described in the previous paragraphs. The multiplication of
this level with the time t results in the sound exposure produced from that specific flight path segment. The
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repetition of the calculation of for all segments of a flight path and the summation of the individual sound
exposures generates the SEL for one single flight. The level increase caused by the number of movements
is added to the SEL. In a second step the whole procedure is repeated for other flight paths and also for
other aircraft types.
Remove! Theres nothing special about aircraft here The only thing thats special is that each vehicle
type has its own source line / flight path. So, there are many more source lines than for the other sources.
But the processing of a source line is exactly the same as for the other sources. The t term is present in alltransport models through the 1/v speed correction. And speed does not need to be constant for the whole
source line, in none of the transport models. We only assume it is constant over a sufficiently small
segment.
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Road noise source
II.2.1.1 Introduction
The road noise emission model describes the noise emission of an "average" European road vehicle interms of a sound power level. The emission model interfaces with the propagation calculation method
described in II.3. The road source methods are described in detail in [ref [52].
The emission model consists of a set of mathematical equations representing the two main noise sources:
a. rolling noise due to the tyre/road interaction; (combined with aerodynamic noise)
b. propulsion noise produced by the driveline (engine, exhaust, etc.) of the vehicle;
The mathematical formulae exhibit the following general form:
)()( ,,, vfBAvL mimimi += , (1)
with f(v) being either a logarithmic function of the vehicle speed v in the case for rolling and aerodynamic
noise, or a linear function with vin the case of propulsion noise. The sound power level Li,mis calculated in
1/3-octaves from 25 Hz to 10 kHz, where the subscript iindicates the spectral frequency band. The index m
represents the vehicle type.
The rolling and propulsion noise production of the road vehicle at the reference speed of 70 km/h is
represented by the values Ai,m. Bi,m.f(v) represents the change in noise production due to a difference in
vehicle speed relative to a reference speed.
The structure of this model, i.e. the form of the equations, as well as the source height definition were
developed within the Harmonoise project. Within IMAGINE, the coefficients needed to calculate the
emission have been established accurately, reliably, and representative of the European average, bymeans of measurements. Also, the category of Powered Two-Wheelers has been added, which had
received no attention in Harmonoise.
Regional correction factors have been added to account for deviations of the local or national vehicle fleet
from the European average, and other correction factors have been added, extended, or reviewed.
II.2.1.2 How to determine the sound power level
Vehicle classes
The road noise model predicts the source emission levels for four main vehicle classes:
1. Light motor vehicles (passenger cars and light vans)
2. Medium heavy vehicles (heavy vans and trucks with 2 axles and 6 wheels)
3. Heavy duty vehicles (trucks with more than 2 axles)
4. Powered Two-Wheelers (scooters/mopeds and motorcycles)
The vehicle classification scheme was developed within the Harmonoise project ref. [54], With respect to
this project, the category of Other heavy vehicles has been deleted.
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Point sources
source at 30 cm
figure 1 Noise source positions
For the calculation of the noise emission LW, each vehicle is represented by one or two point sources, which
are depicted in
figure 1 above. The lowest source is located at 0,01 m above the road; the highest source is located at
0,3 m for light motor vehicles and at 0,75 m for heavy motor vehicles. For two-wheelers, only the 30 cm
source height is used; since the contribution of rolling noise for these vehicles is assumed to be negligible,
the main noise sources are located between 20 and 50 cm.
It is assumed that rolling noise is distributed 80% to the lower position and 20% to the higher position and
that propulsion noise is distributed 20% to the lower position and 80% to the higher position.
The horizontal resolution of the point sourcesis not relevant since a traffic stream will be represented by a line
source. This line source is located at the centre of the road lane.
Source equations
For rolling noise, the general accepted and widely validated logarithmic relation between sound power and
rolling speed is used. The emission LWRis formulated as follows:
+=
ref
RRWRv
vBAL log ,
where, as stated above, the coefficientsARand BRare given in 1/3-octave bands for each vehicle class, and
vref= 70 km/h.
The propulsion noise emission LWPincludes all contributions from engine, exhaust, gears, air intake, etc.For
propulsion noise, the emission LWP is formulated as follows:
ref
refPPWP
v
vvBAL
+= + Cp .a,
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How does the equivalent acceleration relates to ramps? Uphill driving causes important increases in noiselevels due to 2 effects:
1) engine noise
2) decrease in speed (longer exposure times)
Please tell us how to estimate these effects. Isabel told me there was data available for speed profiles onlong steep hills. Where are these? And what about the propulsion noise?.
Every day ten thousands of trucks cross the mountains from France to Spain, from France to Italy, from Italyto Germany. Mostly though narrow valleys This is a source of noise for hundreds of thousands ofEuropean citizens.
where the coefficientsAPBPand Cpare given in 1/3-octave bands for each vehicle class, vref= 70 km/h and
a1is the vehicle acceleration in m/s2.
Correction factors
The source model has correction factors for the following parameters:
for rolling noise:o road surface type (mostly speed dependent and per frequency band)
o road surface age and wetness
for propulsion noise:o vehicle acceleration and deceleration, frequency dependent
o ramps
on the overall level:o horizontal and vertical directivity of the sources, for certain frequency ranges
for variations in vehicle fleet:o % of Diesel vs. petrol engines
o use of winter and studded tyres, and traction tyres for trucks
o vehicle weight and tyre width, which are related
o illegal replacement exhaust systems
Detailed descriptions of these correction factors can be found in ref. [52].
II.2.1.3 Road source input data
To predict the total sound power level of a traffic stream on a road, the necessary input is:
the number of vehicles per class (light motor vehicles, medium heavy vehicles, heavy dutyvehicles, powered two-wheelers), per unit of time (usually one hour), per day, evening and night
period. The input comes from databases, statistics or traffic models (described in II.2.3);
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Programme SILVIA has developed data collection methods for the influence of road surfaces, the results of
which can be directly integrated with the Imagine road noise model.
An ISO recommendation for the assessment of the road surface effects is to use a CPX measurement, that
can determine the effect of the road surface while driving over the road (ref. [56] ).
Statistical data for the vehicle fleet can usually be gathered from national traffic bodies. For instance, thenational database of license plate registrations usually includes data on engine fuel type and vehicle weight
or engine displacement volume. Relations between the latter two and the tyre width, which is the parameter
of influence on rolling noise, can be found in our deliverable. Gathering data on winter or studded tyres can
be more challenging, unless the use of these tyres is obligatory in certain periods of the year, as is the case
in some Nordic countries. Otherwise, counting the number of winter tyres on vehicles in parking lots has
proved to be a relatively reliable and easy method of gathering these data.
II.2.1.5 Links with other IMAGINE Work Packages
The road noise model calculates the instantaneous sound power level of a single vehicle, as a function of its
vehicle class, speed, and many other parameters. To calculate the sound power level of an entire trafficstream on a road section, traffic data are needed.
If this information is not available from other sources, guidelines for gathering these traffic data are
described in II.2.3 and [16].These guidelines describe the best way of obtaining the data for several levels of
traffic models, and where to improve currently existing models, if so desired.
The processes involved for the final noise mapping exercise using GIS are described in II.3 and ref. [3] and
ref. [4].
Methods on how to carry out additional short-term and long-term road noise measurements, have been
developed in ref. [27].
II.2.2 Road Traffic flow modelling
II.2.2.1 Introduction
For the input of the road noise source model it is possible to use traffic flow models. Traffic flow modelling is
treated as a separate subject in IMAGINE to establish an efficient link between traffic flow management and
road noise mapping. The resulting requirements and guidelines for noise mapping and action planning are
described in ref. [16].
The requirements of the Harmonoise/Imagine method for traffic flow (numbers, classes, vehicle speeds etc)
were met by reviewing alternative traffic modelling strategies. This allows the end user to:
judge whether the traffic model available can deliver the desired data, to an acceptable accuracy;
choose an appropriate traffic model (for noise mapping of main roads or of agglomerations, or fornoise action planning); and
review the possibilities for refinement of the traffic model and ways of implementation of theseimprovements.
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Also, guidance is given for the situation in which no traffic model is available.
Traffic models can, depending on the type of model, provide aggregated flow data (e.g. flows and speeds
per hour or per period of the day) or individual vehicle data (e.g. vehicle type, speed and acceleration) for
the road sections included in the noise calculations. Both can be handled by the source model, but when the
traffic data is provided to the source model in the form of individual vehicle data, the resulting noise levels
from individual vehicles need to be aggregated to obtain the noise levels for the desired periods of the day.
Statistics might help to reduce the computational effort! The law of large numbers works remarkably well
for large numbers.
For noise mapping, traffic flow data can be provided by traffic models, or measured on the road. For main
roads, measuring traffic flow data might be feasible. For an agglomeration using a traffic model is the more
logical option. For action planning, a traffic model is needed to estimate the effect of measures to reduce
noise.
The Good Practice Guide for Noise Mapping V2 (see General References [ref]) provides default values if
no, or very limited traffic data is available.
II.2.2.2 Road Traffic flow input data
Input required for road traffic models
Traffic models require quite a large amount of information. In most cases, an existing model will be used, in
which most of the data needed is already incorporated. Generally, the traffic demand is first estimated,
based on:
socio-economic data: land use (number of household/inhabitants, jobs, schools, etc.), income, carownership, travel and parking costs, etc.;
road network representation; travel data for the periods modelled (for noise, that would be day, evening and night, ideally).
The traffic then needs to be assigned to the road network. For this, data are needed on network layout.
Depending on the model type (macroscopic vs. microscopic), this may be more or less detailed, and include
ata on:
zones with properties (e.g. socio-economic data, parking costs);
nodes with properties (e.g. crossing penalty);
links with properties (from node, to node, length, capacity/number of lanes, free flow speed).
For some traffic models, input is needed on traffic control systems (e.g. traffic lights), and traveller/driver
properties and vehicle properties (vehicle stock).
Checks on input of road traffic models
Traffic models were not developed for environmental analyses, so it should be checked to what extent an
available model is suitable for noise mapping. Common problems are:
the traffic model does not distinguish between the vehicle types as used in the noise model;
the traffic model does not cover the periods (day-evening-night) as used in the noise model;
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the traffic model for an agglomeration does not include all roads in the network;
the traffic model does not have information on road gradients;
the traffic model does not provide data on speed distributions and/or accelerations (which may beimportant in urban areas, near intersections).
Output of road traffic models
The output of traffic models differs per type of model, and even between different models of the same type.
All of them can provide data on:
traffic volumes;
average speeds.
Some models (mainly microscopic models) provide additional data on speed distributions and/or
accelerations.
II.2.2.3 Methods of data collection
Road Traffic flow data
There are many different ways to obtain traffic flow data. Inductive Detector Loops (IDLs) are the current,
de-facto standard for in-situ detectors, and may be expected to provide a considerable volume of
information for mapping. Other technologies, whilst not yet routinely deployed, provide comparable
performance to IDLs. Almost all reviewed technologies may prove adequate for noise modelling purposes
with some minor caveats regarding deployment location, performance in inclement weather conditions and
cost of operation. The use of video techniques and fusion of multiple sensors are rapidly developing areas.
Regarding in-vehicle systems, the operations of commercial service providers and continuing
advancements of satellite tracking technologies offer the possibilities of collecting journey information
across extensive areas of the continent.
There is a growing trend for traffic (and other) information from both main roads and in agglomerations to be
checked processed and stored in unified databases. These databases are housed at Traffic Management
Centres (TMCs) or Urban Traffic Control Centres (UTCs) and offer analysis of long-term traffic patterns, and
the potential for continual validation of mapping exercise results.
It is recognised that, by the time the HARMONOISE methods are first used in practice, considerable
experience will have been developed in handling large volumes of traffic information from the interim round
of mapping (2007). This experience will add to knowledge gained through the continued operation of air-
quality management systems and supplement additional traffic information published by relevant authoritiesor agencies.
Technical report 2.4 - Collection Methods for Additional Data provides more information on methods to
collect traffic flow data.
II.2.2.4 Links between road traffic modelling and other IMAGINE Work Packages
When traffic and noise modellers discuss potential improvements to the traffic modelling process, to obtain
the best possible data for the noise model, they will need to weigh costs and benefits. In that respect, it is
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important to know to what traffic parameters the closest attention should be paid. The following list gives the
traffic parameters in order of importance for the noise modelling process:
vehicle speeds & traffic composition;
vehicle flows;
acceleration/deceleration;
speed distributions;
(data regarding the above parameters on) low flow roads.
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II.2.3 Rail noise source
II.2.3.1 Introduction
Railway noise comprises the combination of a number of complex sources that can all be dominant under
different modes of operation. At low speed, traction noise, eg the noise from engine exhaust, the engine
carcass, compressors, fans, will dominate. At very high speed, aerodynamic noise, generated at
discontinuities in the vehicle body and at the current-collecting pantograph, is dominant. However, over a
very wide speed range, rolling noise is dominant. The figure below illustrates this.
Not only do these sources have different characteristics, but they also occur at different heights above the
rail head, as can be seen in the following figure.
10 20 50 100 200 300 400
70
80
90
100
110
120
130 Sound pressure level as function of train speed
SoundpressureleveldB(A)
Train speed [km/h]
Traction noise
Rolling noise
Aerodynamic noise
Total
10 20 50 100 200 300 400
70
80
90
100
110
120
130
10 20 50 100 200 300 400
70
80
90
100
110
120
130 Sound pressure level as function of train speed
SoundpressureleveldB(A)
Train speed [km/h]
Traction noise
Rolling noise
Aerodynamic noise
Total
0m, rolling: track
0.5m, rolling: wheel, aero,
traction, brake/ curve squeal,
braking
2m, traction
3m, traction
4m, traction, aero
0m, rolling: track
0.5m, rolling: wheel, aero,
traction, brake/ curve squeal,
braking
2m, traction
3m, traction
4m, traction, aero
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In the IMAGINE Railway method the rolling noise mechanism is divided into an excitation element and a
noise emission element. The track and wheel roughness, which form the excitation element, are separately
described, and can be summed to represent the combined roughness (taking into account contact filter
effects).
The noise emission is generated by a forced vibration mechanism which transforms the total excitation
(combined roughness) into noise. This