DISCUSSION
Various sources of noise pollution Traffic noise is of two types. Noise generated by individual vehicles and by continuous flow of vehicles of all types. Noise from engines and transmission depends upon the design of vehicles and particularly upon the method of support used for its moving parts. More expensive vehicles employ more elaborate damping system so that noises are not transmitted to the body of the vehicle. Considerable improvements are made to improve engine mounting systems. An efficient silencing system is able to reduce the power output to any engine. In consequence the design of the exhaust system is a matter of compromise. Systems usually designed to keep within the law without significantly affect the cost and performance.