imagine - guidance on the imagine methods

8/10/2019 IMAGINE - Guidance on the Imagine methods

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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.2.4.3 Rail source input data........................................................................................................................................................................... 34

II.2.4.4 Methods of data collection/measurement methods ............................................................................................................................. 35


II.2.5 Industrial noise.......................................................................................................................................................................................... 37


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II.2.5.1 Introduction.......................................................................................................................................................................................... 37


II.2.5.3 The input and output.......................... .................................................................................................................................................. 38

II.2.5.4 Measurement methods......................... ................................................................................................................................................ 39


II.2.6 Aircraft noise............................................................................................................................................................................................. 41II.2.6.1 Introduction.......................................................................................................................................................................................... 41


II.2.6.3 The input and output.......................... .................................................................................................................................................. 42

II.2.6.4 Methods of data collection/measurement methods ............................................................................................................................. 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


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


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

imagine - guidance on the imagine methods

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