Abstract
Due to growing interest on environmental questions, reduction of noise emission has became more important issue among automotive and related industry. Reduction of noise means new challenges and at the same time gives new business opportunities.
In spite of the fact that sound and noise are very familiar words, their definition is not totally clear. Terminology and equations concerning sound itself are quite often misunderstood in general discussion of every day newspapers. Noise has different types of affects on health of the people who are exposed to noise. Noise causes healthy problems both directly and indirectly. Authorities in different countries are looking for methods for protecting their citizens from noise with reasonable costs. Quite commonly authorities enact laws and regulations which force for example automotive industry to look for solutions to reduce noise.
Due increased interest on noise of cars and vans, several standard measurements have been developed for measuring noise caused by vehicles and tires. Also road administration authorities in several countries have paid more attention on road pavement construction and its affect on the noise emitted.
Laboratory of Automotive Engineering in Helsinki University of Technology has designed, implemented and utilized a HUT NOTRA (Helsinki University of Technology, Noise Trailer) for measuring pavements and for comparing tyres.