Engineering Acoustics

14Surface Transportation Noise and Vibration Sources and Control

14.1 Introduction

The number of vehicles on the road continues to increase worldwide. Road traffic noise is really a greater problem than aircraft noise in most countries since it affects many more people. The noise of railroad and rapid transit vehicles is also a problem for people living near to rail lines. Noise and vibration sources in road and rail vehicles and aircraft affect not only the occupants but nontravelers as well. Major sources consist of (i) those related to the power plants and (ii) those non‐power‐plant sources generated by the vehicle motion. Most rail and rapid transit vehicles have power plant noise and vibration sources that are similar to road vehicles. With rail and rapid transit vehicles, however, tires are mostly replaced with metal wheels, and the wheel–rail interaction becomes a major source of noise and vibration. Brake, gearbox, and transmission noise and vibration are additional problems in road and rail vehicles. Interior noise level criteria depend upon the vehicle type and the occupied space considered. For passengers, speech communication and privacy are the main concerns, while for truck, railroad vehicle, and ship engine room operators and crew, hearing protection and speech communication remain important issues.

14.2 Automobile and Truck Noise Sources and Control

In cars, trucks, and busses, major power plant noise sources include gasoline and diesel engines, cooling fans, ...