The objectives of this study were to investigate the effect interrupted traffic flow has on traffic noise and to determine an applicable adjustment factor. No attempt was made to develop a specific equation to predict noise levels at interrupted flow locations.

The basic method of analysis consisted of comparing the field data taken at intersections to determine if the measured noise levels changed as a function of distance from the intersection. Results showed that interrupted flow conditions did not cause an increase in the L10 and Leq noise levels. Data taken before and after the installation of traffic signals showed that the addition of traffic signals did not significantly affect the average noise level. A comparison of measured and predicted noise levels showed general agreement.

It was concluded that no adjustment factor is necessary to account for interrupted flow. It was recommended that the current procedure used for interrupted flow locations be continued. In this procedure, no adjustment factor is used, and the traffic speed used in the prediction is the free flowing vehicle speed (speed limit).

Report Date


Report Number

No. 542

Digital Object Identifier



The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Bureau of Highways. The report does not represent a standard, specification, or regulation.