NOISE CONTROL FOR MOTOR VEHICLES: HOW FAR SHOULD WE GO?

While General Motors Corporation believes in the necessity of a federal noise control act to achieve uniformity of standards across the nation, it does not concur with the proposed federal noise level of 80 dBA at 50 ft (15 m) from the lane of travel for speeds less than 35 mph (56 km/h) for vehicles weighing more than 10,000 lb (4540 kg) GVWR. It is suggested that the value of such a regulation be considered carefully, and a decision relative to the proposed regulation be reserved until the effectiveness of the regulation at 83 dBA (effective October 1975) including enforcement can be evaluated. After pointing out that, when designing a vehicle to meet a regulated level, a manufacturer must establish a design margin sufficiently below that standard to assure that vehicles will comply, the following statements are made: (1) The cost of trucks per dB reduction in sound level rises rapidly at the mean level is decreased below 80 dBA; (2) in terms of the number of people exposed to various sound levels and the degree of reduction of that exposure, the benefit per dB reduction diminishes as the sound of the vehicles perceived by the listerners approaches the background levels established by tires and other ambient noise; and (3) therefore, the cost-benefit ratio, which is a function of both of the above effects, increases rapidly as the noise level of trucks is reduced below the range of 80 to 81 dBA. The conclusion from these statements and other facts pointed out in this paper is that truck noise levels lower than 83 dBA are not cost-effective.

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Filing Info

  • Accession Number: 00098526
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Aug 27 1975 12:00AM