Citation

Plummer RW, King LE. Highw. Res. Rec. 1973; 445: 34-44.

Copyright

(Copyright © 1973, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

The manual on uniform traffic control devices for streets and highways sets forth the conditions under which combinations of signal colors and turn arrows should be used at signal-controlled intersections. These recommednations have been generally accepted and complied with except in the case where a left-turning movement at an intersection is to be terminated while the through movement continues. In many instances, due to the physical limitations of an intersection or for reasons of economy, it is difficult to comply with this standard. Present practice at such location is to mount a fourth lens displaying a turn arrow either on the through face or adjacent to it. Installations such as this result in a wide variety of clearance interval indications. This research project was designed to develop a standard for this situtaion. A literature review and mailed questionnaire were employed to determine present practices. A controlled laboratory study, utilizing both color movies and color slides, investigated 19 signal indications for their effectiveness in conveying their intended message to the driver. The collection of accuracy and reaction time data was analyzed by an analysis of variance and the newton- keuls test. Four of the indications proved superior and were tested further under actual field conditions. Based on the analysis of the driver performance data recorded in the field study, a single indication was recommended.

Language: en

Keywords

TRAFFIC SIGNS, SIGNALS AND MARKINGS; ROADS AND STREETS - Intersections; STREET TRAFFIC CONTROL