Abstract
Long-term acceptance of motorcycles as a part of an individual traffic system requires improvements in environmental effects. Especially the characteristic noise of motorcycles in combination with high motorcycle traffic on specific roads during motorcycle season causes
(sometimes severe) problems among area residents.
Motorcycle manufacturers optimise their vehicles in order to meet legal requirements. But as current pass-by noise measurement standards (e.g., based on ISO R 362) concentrate on only one driving state (i.e., full throttle acceleration at 50 km/h in 2nd and 3rd gear), they do not consider the drivers habits in real traffic. Especially for high-performance motorcycles with wide engine speed ranges, the noise level emitted depends on engine speed more than on throttle position. So the driver has a superior influence on the noise emitted by his bike via his driving behaviour and gear change strategy.
Measurements performed at Darmstadt University of Technology, Automotive Engineering Department, monitored the typical driving behaviour of a representative group of motorcyclists consisting of 30 persons in real traffic with a track length of 100 km. During the test drives characteristic parameters such as vehicle speed, engine revolutions and throttle position were monitored.
Moreover, for the motorcycles used, the pass-by noise emissions were measured on a test track varying engine speed, throttle position and used gear. From these measurements, complete maps of noise emissions depending on the driving condition (gear, speed, engine load) were developed. Combining the noise maps and the driving data of the drivers in real traffic, real traffic motorcycle noise emissions and the drivers influence on these emissions were derived.
This paper presents some statistical analyses of typical driving habits of motorcyclists and their effects on motorcycle real traffic pass-by noise. These traffic results are compared to noise measurements under current statutory conditions.
The results can give advice as well to the legislators to create more practically oriented testing methods as to the motorcycle manufacturers in order to find optimum vehicle layouts considering the reality of traffic.