Estimates of the reduction of traffic noise following the introduction of quieter vehicles.

The effect on traffic noise of reducing vehicle noise is predicted. The prediction was made using a computer model which assumed two categories of vehicle in the traffic stream, light vehicles less than or equal to 15 t. & heavy vehicles exceeding 1.5 t. It is shown that quietening heavy vehicles brings an appreciable reduction of traffic noise for streams containing 20% or more heavy vehicles and is most effective for high flows.