Tire-road noise emission is an environmental issue which affects the life of the majority of the people. The governments set limits of the so called coast-by noise which is measured close to a road while a vehicle is passing by under free rolling driving condition at defined speed. A special road pavement has to be used to do this tire approval test. It is well known that there is a wide spread of the coast-by noise level measured on different realizations of this ISO 10844 standard track using identical tires and vehicle. Even in the case that sound pressure level corrections were made concerning tire, track or air temperature, wheel load and inflation pressure, there is a remaining variance which covers the full noise level range which can be covered by tire design changes.
To characterize the ISO track noise quality several quantities are specified by the standard, in which the mean profile depth and the acoustical absorption are most prominent. From the observed large variance of noise results on different tracks which are all within the specification of ISO 10844, it can be concluded that there are more influencing factors on tire-road noise emission than considered in the standard so far.
The main goal of the project is to investigate the influencing factors on the tire-road noise emission with a special focus on road surface parameters. The research is addressing three research questions:
- How far it is possible to predict the coast-by noise level based on the parameters used to specify the road pavement according to ISO 10844?
- Which additional road surface parameters are necessary to make more accurate coast-by noise level predictions? Which prediction quality can be achieved?
- What is the distribution of the ISO and the additional road surface parameters on public roads? What about the representativeness of ISO 10844 tracks?