Surface Transportation. III

As technology advances, the level of noise in our everyday environment appears to increase. Among the factors contributing to this in the traffic field are the increased horsepower used in vehicles, the reduction in weight of engines, the higher compression ratios, and the increased use (especially in buses and trucks) of diesel engines. Legislative control has so far been somewhat timid and lacking the followthrough of enforcement. Noise‐control technology has been applied only sporadically, so that the range of noise commonly encountered in any octave band for standard‐size passenger cars is more than 10 dB. For heavy trucks, it is even greater. Motorcycles at full throttle, almost regardless of speed, exceed the noise of tractor trailors crusing at 60 mph. Stationary baffles have been successfully used, especially for trains. Rubber tires have also been found practical in subways and urban trains. Proper highway location, design, and noise zoning are further means toward a quieter community.