Efficacy of Red and Yellow Turn Arrows in Traffic Signals

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Efficacy of Red and Yellow Turn Arrows in Traffic Signals

H. A. M. Flanakin / M. A. Kraft / T. VanVechten

The objective of the study was determination of efficacy of red, yellow and green turn arrow indications in traffic signals. Four basic study methods were: (1) history of traffic signals and use of arrows for traffic controls; (2) determination of current practices among traffic engineers throughout the Nation; (3) public understanding and acceptance of arrow indications in lieu of conventional circular lenses in traffic signals through the medium of questionnaires mailed in by highway users; and (4) before and after field studies, by time-lapse photography, to determine motorist response, accident experience and cost effectiveness at six experimental sites in Washington, D.C. and two sites in the suburban area of Montgomery County, Maryland. All elements of the study are described in detail. Arrows were found to be beneficial in some circumstances. Conclusions and recommendations, are expressed. Guidelines for use of three color turn arrow displays have been developed, and a Users Manual to aid in implementing arrow displays, is included.