00149195

Component

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This research to improve existing criteria for time-varying highway noise included investigations of the effects of such noise on speed, communication, annoyance and sleep. Speech intelligibility tests were conducted in the presence of recorded traffic noise to assess the effect of the variability of that noise on verbal communication. Annoyance was studied using a 5-point adjective category scale and noise samples from the speech intelligibility tests. Sleep interference studies were restricted to a literature review and the results of BBN sleep studies near the Los Angeles airport. Details are given of the tests and equipment. The findings are presented and discussed. The results indicate that the most stable noise measure for predicting annoyance is the Equivalent Noise Level (L sub eq), and that this level is an adequate predictor of speech interference for traffic noise distributions whose L sub 10 minus L sub 50 values range from 0.4 dB to 7.8 dB. Conclusions relating to annoyance judgements, the L sub eq ratings, and sleep interference are also presented. The recommendation is made that criteria for the effects of traffic noise on people be expressed in terms of L sub eq. It is also recommended that the L sub eq measure of traffic noise be used to evaluate (1) the more extreme cases of traffic noise variations that occur in typical spaces occupied by people, and (2) the order and grouping of effects of vehicles on subjective assessment of traffic noise.

This report appeared in National Cooperative Highway Research Program Summary of Progress Through 1976.

00149194

Project 3-7

p. 141-152

1976

NCHRP Summary of Progress

Figures (9) ; References (3) ; Tables (4)

Annoyance; Forecasting; Sleep; Standards; Traffic noise

Criteria

Administration and Management; Design; Highways; Operations and Traffic Management; Safety and Human Factors

TRIS, TRB

Mar 30 1977 12:00AM