International literature published to date has considered that tyre/surface noise does not have a significant effect on road noise for speeds below 60 kilometres per hour, and that a 3 dBA noise level change is just noticeable to most people. This makes the widely observed increases in community annoyance from road resealing hard to explain. The first part of this research investigates the effect that road surface type has on road traffic noise at urban driving speeds (50 kilometres per hour), and finds that the road surface does have a significant effect, with the surface contribution varying by up to 7 dBA between common New Zealand surface types. The effects of each surface differed for heavy and light vehicles, but were consistent over all tested driving speeds. The second part of the research investigates the consequent effect on community annoyance, and finds that small changes in traffic noise level of as little as 1 dBA are matched with changes in Behavioural Disturbance. The Behavioural Disturbance Index was found to be a more sensitive measure of noise annoyance than traditionally offered techniques. Finally, guidance on including noise considerations in road surface selection is offered. (Author/publisher)
Abstract