Abstract
This paper describes evidence that insufficient allowance is being made for road surface effects on traffic noise in New Zealand urban areas where vehicle speeds are typically 50 km/h. Therefore low noise road surfaces could have much greater benefit in reducing community annoyance with noise in urban areas than was previously thought. A drive,by technique, which captures both the noise level and a spectral distribution of the noise from test vehicles, and from samples of actual vehicles within vehicle streams, was used to measure the noise from a range of road surfaces. It was found that, at 40,50kmph, when compared to dense graded asphalt, the most commonly used road surfaces (the chip surfaces) may be 3 to 6dBA noisier for cars, and 0 to 2dBA noisier for trucks. These effects are much larger than is anticipated by commonly used road noise models. Populations adjacent to roads being resurfaced were surveyed using both annoyance and behavioural scales. It was found that surface type was significant in influencing traffic noise annoyance of people living next to the roads, and that changes in behaviour could be detected for very small changes in noise, i.e. less than 2dBA