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SOPRANOISE targets a three-step approach for assessing the in-situ intrinsic acoustic performance of road/railway noise barriers in regard to airborne sound insulation and sound reflection under direct sound field conditions. This approach goes from the in-situ inspections method (targeting at the acoustic effect in the far-field) to the standardized measuring methods EN 1793-5 and 6, with "quick and safe" measuring methods in between. Papers about SOPRANOISE have already been presented in 2020 and 2021 as progress reports. The research ended in February 2022 and the final outcomes are now presented. The main part of the pending work has been done within Work Package 4 (WP4). Herein, a new "quick and safe" method was designed and validated both in the lab and in situ. The new measuring equipment is portable, lightweight and uses a linear antenna; the measurement itself is fully automated and the results show a very good correlation with full EN 1793-5/-6 results. WP4 results are particularly successful and, together with the in-situ inspection, those methods are ready to be submitted to the relevant CEN/TC226/WG6 working group to draft a new framework on noise barriers assessment. All main reports are public available on the SOPRANOISE and CEDR webpages.

In the frame of the SOPRANOISE project (funded by CEDR in the Transnational Road Research Programme 2018) the database of the European noise barrier market developed during the QUIESST project was updated with newly acquired data. This database gives the opportunity for an empirical study on the correlation between the different measurement methods for the acoustic properties of noise barriers (according to the EN 1793 series) to further investigate the interrelationships between these methods by using single-number ratings and third-octave band data. First a correlation of the measurement methods for sound absorption under diffuse field conditions (EN 1793-1) and sound reflection under direct sound field conditions (EN 1793-5) is presented. Secondly, a correlation of the measurement methods for airborne sound insulation under diffuse field conditions (EN 1793-2) and airborne sound insulation under direct sound field conditions (EN 1793-6) is shown. While for airborne sound insulation a distinct correlation is found due to the wide data range, for sound absorption no robust correlation can be found.

The effect of railway platforms on sound propagation has thus far not been investigated in detail. Due to the vicinity to the track, the platform’s large reflecting horizontal surface, and the often present canopy it is unclear whether standard noise propagation prediction methods can be applied without modifications. Here, the acoustic effect of low railway platforms was investigated using measurements directly at the platform as well as in the distance in order to derive suitable models for the 2.5D boundary element method (BEM) as well as for standardized prediction methods. For the BEM using a source at the center of the track at the height of the platform edge was found to be an optimal solution. Different standard platform variations were investigated. The results show a relatively small, low lying, and localized shielding effect of the platform of up to 3 dB that further diminishes with increasing platform width. In comparison, a low noise barrier at the same position yields up to 4 dB and the effect is less localized. Although a canopy may lead to a better protection of elevated positions, the presence of such a structure also leads to a further decrease of the platform shielding in lower positions. Absorption on the lower side of the canopy can reduce this undesirable effect, however, only when large portions of the canopy are covered with absorbing material. Using the BE calculations and the measurements, two standardized calculation schemes, i.e. the Austrian ONR 305011 and the noise assessment methods defined in the European Directive 2015/996 (EU) were investigated. Both methods overestimate the platform effect. Similar to the BEM, a better agreement is reached when the source position is adjusted to the platform height. Floating elements such as a canopy are not defined in any of these standards, however, non-standard calculations of such objects as already implemented in certain noise mapping software could be used to take into account the attenuation effect for certain receiver positions.

The CNOSSOS-EU method is recommended in Europe for environmental noise prediction. In regards to road traffic, it includes vehicle noise emission models implicitly referring to internal combustion vehicles. The development of electrically driven vehicles calls for the future consideration of these vehicles in prediction models. On the basis of experimental data, the study reported in this paper proposes a noise emission model for extending CNOSSOS-EU to light electric vehicles. Correction terms to be applied to the propulsion noise component are determined. Investigations on a sample of tyres with good rolling resistance performance, which is a main tyre selection criterion on these vehicles, indicated that no correction is required for the rolling noise component. Differences between the noise emission from conventional vehicles and electric vehicles are discussed for several road surfaces. Owing to the limited vehicle sample as well as transitional statements, this new model for electric vehicles running at constant speed over 20 km/h should be considered as a first step towards the definition of this vehicle technology in CNOSSOS-EU.

ROSANNE is a collaborative project in the Seventh EU Framework Programme which aims at developing/harmonising measurement methods for skid resistance, noise emission and rolling resistance of road pavements as a preparation for standardization. To achieve this, the project is following the recommendations of key predecessor projects like TYROSAFE, HERMES, SILVIA, SILENCE and MIRIAM as well as considering the ongoing work in CEN and ISO groups. Work package 1 deals with skid resistance and aims at the harmonization of skid resistance measurement following the TYROSAFE Roadmap, by deriving conversion factors for friction indices based on similar groups of devices, namely longitudinal and sideways skid resistance measurement devices. During the first project year a first round robin test was carried out in Nantes, ten different devices participated to the test. The results of this test are collected in report D1.2 “Analysis of data from the first round of tests and initial development of the common scale”. Work package 2 is dealing with the pavement influence on road traffic noise emission: the main objective of this work package is to combine the existing measurement methods of SPB (ISO 11819-1) and CPX (ISO/DIS 11819-2) into a stable and reliable harmonised pavement noise emission characterisation method. The project is validating procedure incorporating correction mechanisms for temperature influence and investigating its potential use for noise calculation methods like the one proposed by the CNOSSOS-EU project. Work package 3 is dealing with rolling resistance, where the ROSANNE project is mainly building on the results obtained in the MIRIAM project and is considering standardized trailer measurements of rolling resistance coefficients of road surfaces. After a first report D3.1 “State of the art on rolling resistance measurement devices including draft standard outline” the following main report was produced “Parameters influencing rolling resistance and possible correction procedures”. In the frame of work package 4 the project is also exploring the potential for developments in the measurement of surface texture in order to find out parameters that better reflect the physical process of tyre/road interaction and that may improve the understanding of how the texture influences noise emission, skid resistance and rolling resistance. In addition to that this work package is also investigating the performance of reference tyres and pavements which are necessary for the measurement of all three road surface properties. The present paper summarizes the project status after the first 18 project months.

In Europe, in situ measurements of sound reflection and airborne sound insulation of noise barriers are usually done according to CEN/TS 1793-5. This method has been improved substantially during the EU funded QUIESST collaborative project. Within the same framework, an inter-laboratory test has been carried out to assess the repeatability and reproducibility of the newly developed method when applied to real-life samples, including the effect of outdoor weather variability and sample ageing. This article presents the statistical analysis of the inter-laboratory test results, and the values of the repeatability and the reproducibility, both in one-third octave bands and for the single-number ratings. The estimated reproducibility values can be used as the extended measure of uncertainty at the 95% credibility level in compliance with the ISO GUM. The repeatability and reproducibility values associated with airborne sound insulation are also compared with the corresponding values for laboratory measurements in building acoustics and an acceptable agreement is found.

Loudspeaker characteristics can have an appreciable influence on the sound absorption properties obtained with CEN/TS 1793-5 [1] . Although sound sources with omnidirectional radiation properties are favored, these often hold the problem of long impulse responses due to their design potentially incorporating ports [2] . In this paper, the inverse filtering approach is applied to two different sound sources. It is shown that it is a valuable measure to reduce the influence of the loudspeaker characteristics on the obtained sound absorption values. Furthermore, an attempt is made to measure the absorption properties according to CEN/TS 1793-5 without the need for the subtraction procedure of a free-field measurement. Thereby, as long as only high frequencies are considered, reasonable values can be obtained.

TRA2016 - Moving Forward. Innovative Solutions for Tomorrow's Mobility, Varsovie, POLOGNE, 18-/04/2016 - 21/04/2016; With the advent of electric vehicles and their significant lower propulsion noise emission it is possible to assess the tyre-road noise trough cruise-by measurements with an increased accuracy, even at speeds where a combustion engine propulsion system would usually disturb the measurement results. The European project FOREVER (Future OpeRational impacts of Electric Vehicles on European Roads) funded by CEDR between 2013 and 2014, aimed to provide data and information on the potential future noise impacts of electric vehicles (EVs) and hybrid electric vehicles (HEVs) on national roads, more specifically (i) the noise levels generated by electric/hybrid vehicles, (ii) how these vehicles can be effectively included in noise prediction models, and (iii) the likely noise impacts for residents as the number of electric/hybrid vehicles on national roads increases. Within work package 3 of the project, concerned with the noise emission of tyres used on EVs and HEVs, nine different sets of tyres have been selected and compared by carrying out pass-by measurements based on the standard ISO 11819-1. Special attention has been paid to potential and dedicated tyre sets which meet the demands for low energy consumption and a low rolling resistance to optimize the range of electric vehicles. The results have been analysed in order to reveal differences between single tyre sets and to quantify the influence of the tyres on the tyre-road noise. In a second part of the work, the EU tyre labels have been considered. The tyre labels have been introduced by the European Community for informing and helping consumers to choose products according to energy efficiency, safety in wet braking conditions and exterior rolling noise. Minimum requirements are also set in type-approval legislation. In the FOREVER project the exterior noise labels of the nine selected tyres have been compared with the results of the pass-by noise measurements performed on a common real-life road surface. Discrepancies observed on tyre ranking between both approaches have been discussed. Investigations within the concept of 'low-noise tyres' have been put forward accordingly. Finally, outcomes for the modelling of rolling noise from electric vehicles in the European noise assessment method CNOSSOS-EU, which is recommended for strategic noise mapping in Europe, have been given. As a complement to the EV propulsion noise component previously specified in the FOREVER project, it turns out that no correction term is required for EV rolling noise. In this paper, the main content as well as the outcomes of work package 3 of the project FOREVER are presented.

The present document is the final report of Work Package 3 (WP3) of the FOREVER project. The aim of this work package was to investigate potential and dedicated tyres currently used for electric vehicles and their noise output. While Work Package 2 (WP2) takes care of the overall noise emitted by electric and hybrid vehicles, WP3 focusses on the noise emitted by the tyre-road interaction. This particular component of the overall emitted noise has been analysed for a long time, but now, the almost complete absence of motor noise makes measurements of this component also possible at lower speeds. A tyre selection has been performed in order to represent the current market of tyres for electric and hybrid vehicles. As shown by the literature study carried out within task 3.1, the selection of tyres for electric vehicles by car and tyre manufacturers is currently driven by fuel resp. energy efficiency requirements, relying on the rolling resistance performance of the tyre. No relation is currently present between rolling resistance and rolling noise. Ther is currently no evidence of a trend between the rolling resistance performance and the EU rolling noise labels. Using the selected tyres controlled pass-by measurements according to ISO 11819-1 have been performed, and the results have been analysed. As expected from the literature review, the relation between the overall maximum pass-by noise level in dB(A) and the logarithmic vehicle speed is linear, where the maximum contribution to overall noise is evidently coming from the rolling noise. The maximum spread between two investigated tyres never exceeded 3.6 dB for lower speeds (20-50 km/h) and for speeds between 50 and 120 km/h the spread never exceeded 2.4 dB. General similarities in the spectral behaviour could be found in the sample of selected tyres, for example a higher slope of 2 kHz and a lower slope of 500 Hz components to speed in comparison to the most dominant 4kHz band. So the sample showed not only a changing spectral distribution over speed but also a common bahaviour for the tyre sample. The spectra at different speeds give a comparison of occurring peaks and showed the dominance of the 1 kHz octave band. Additionally, the case studies analysed the differences between the selected tyres in detail. Spectral components can rise differently with speed so the relative difference of the distribution changes. Nevertheless these differences have only little relevance on the overall levels. Investigations conducted on noise measurements at pass-by of the two electric vehicles successively fitted with nine different tyre sets (eight sets on the first vehicle, one set on the second vehicle) did not bring to light any relation between the exterior noise EU-label and the noise on actual road surfaces, in particular regarding tyre ranking. This has impacts on the concept of low-noise tyres since a possible requirement on the limit value based on the EU-label would not lead to select the quietest tyres on actual dense road surfaces and would probably not modify the roadside traffic noise. Tyres designed or selected by manufacturers for EVs have no effect on global rolling noise compared to conventional tyres. A wider set of EV-specific tyres is required to conclude on frequency differences possibly impacting the roadside traffic noise. On the basis of current knowledge, it turns out that rolling noise from light electric vehicles does not differ from conventional vehicles. Thus, for predictions of traffic noise according to the European assessment method, the use of the rolling noise component given in CNOSSOS-EU remains available without amendment for light electric vehicles. Only the propulsion noise component requires correction terms, as proposed in the final report of Work Package 2 of the FOREVER project.

Noise barriers are one of the primary means in noise abatement for traffic-related noise in the proximity of roads and railways. The efficiency of noise barriers concerning sound absorption and sound insulation nowadays is evaluated with different experimental methods. On the other hand, simulations are very helpful for noise barrier manufacturers and are a cost-efficient tool for predicting and planning new noise barrier solutions. In the following paper, the focus is placed on the vibro-acoustical interactions of noise barriers with the surrounding sound field. This means that the sound produces a vibration in the barrier which then emits additional sound waves. This aspect, often ignored, is responsible for the transmission of sound through the noise barrier. Boundary and finite elements methods are best suited to simulate this kind of interaction. Simulations have been performed and different sound sources (plane wave, point source, line source) have been analysed.

Traffic-related noise has been increasing steadily. Noise barriers are one of the main tools used for noise abatement, and there is still potential for optimization and improvement of the acoustic performance by employing non-standard designs. Simulations are a cost-efficient tool for predicting and planning new noise barrier solutions. The following paper studies some non-standard barrier shapes with particular focus on the formation of a virtual soft-plane for some frequencies. Destructive diffraction from the top edge of the barrier is used in order to optimize the shielding effect of the barrier. Through the use of 2D-BEM simulations different barrier profiles and their effect of shielding are studied. The focus is to obtain useful shielding in the farfield region with intelligent shapes thus permitting a reduction of the barrier height.

The FOREVER (Future OpeRational impacts of Electric Vehicles on national European Roads) project was commissioned, as part of the CEDR Transnational Road Research Programme Call 2012 on Noise, to provide information to NRAs with respect to this issue. The project was developed with three key objectives: - To identify the noise emission levels from electric and hybrid vehicles. This has been achieved through practical measurements of noise from electric and hybrid cars, vans and trucks. The information has been used to develop correction factors to allow such vehicles to be included within state-of-the-art noise prediction models and to investigate subjective responses to these vehicles when part of traffic on NRA roads. - To identify the noise emission of tyres used on electric and hybrid vehicles. This has been achieved through practical measurements of noise for different types of tyres, with the aim of identifying whether specific tyres are/can be used for electric vehicles. - To assess the potential future noise impacts of electric and hybrid vehicles. A state-of-the-art noise prediction model has been used, with data from the practical trials, to assess the noise impacts close to the road for a range of different road type/traffic speed/traffic composition scenarios.