Calculations have been performed to assess the potential effectiveness of barriers toward reducing noise exposure from the federal-aid highway system. Noise exposure, in terms of the numbers of people exposed to Ldn greater than 60, 65, 70, and 75 dB, from the primary federal aid system was computed for present traffic flow and projected traffic through the year 2000. Reductions in noise exposure were computed for several scenarios of constructing barriers along urban interstate highways. It was found that significant reduction of noise exposure would require barriers along most of the urban interstate system. The benefit (in terms of reduction of exposed population) per mile of barrier construction was found to be greatest at high noise levels (Ldn greater or equal to 75 dB). It was concluded that barriers would not provide a feasible method for abating noise on a national scale. Their main benefit is to provide relief in extremely noisy local applications.

Prepared by Wyle Laboratories, Wyle Research, Arlington, Va., under contract no. 68-01-4374. Issued July 1978. Includes bibliographical references. Microfiche.