The U.S. Department of Transportation, Research and Special Programs Administration, Volpe National Transportation Systems Center, in support of the Federal Railroad Administration is conducting a research program with the goal of reducing the number of fatalities and injuries at highway-railroad grade crossings. As part of this program, a study is being conducted to determine the effectiveness of railroad horn systems in reducing accidents at highway-railroad grade crossings. An earlier report in the series entitled Study of the Acoustic Characteristics of Railroad Horn Systems , presented the acoustic characteristics of several types of railroad horn systems. This report addresses the effectiveness of railroad horn systems and their resulting impact on the community noise environment. The insertion loss and interior noise levels of several motor vehicles were measured to determine if the warning signals created by railroad horn systems provide effective warning for the motorist. Acoustic data were also obtained for a horn system through wayside measurements of in-service locomotives to determine the community noise exposure. Also addressed is the distance from the crossing at which the signaling cycle should be actuated to minimize the community noise exposure.