FIELD INVESTIGATION OF DRIVER UNDERSTANDING OF LEFT TURN SIGNAL INDICATION SEQUENCES

In the case where a left turning movement at an intersection is to be terminated while the straight-through movement continues, the Manual on Uniform Traffic Control Devices requires that a separate signal face, consisting of circular red and yellow lenses and a green turn arrow lens, be provided to control the turning movement. In many instances the physical limitations of an intersection or for reasons of economy it is difficult to comply with this standard. Present practice at such locations 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 situation. A literature review and mailed questionnaire were employed to determine present practices. A controlled laboratory study, utilizing both color movies and color slides, investigated nineteen signal indications for their effectiveness. Four of the indications were further tested under actual field conditions. Based upon the results of the study, a single indication was recommended. /HSRI/

  • Supplemental Notes:
    • Technology For Man 72. Proceedings of the Sixteenth Annual Meeting of the Human Factors Society, Santa Monica, October 1972
  • Corporate Authors:

    Human Factors Society

    1134 Montana
    Santa Monica, CA  USA  90403
  • Authors:
    • King, L E
    • Plummer, R W
  • Publication Date: 1972-10

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 6 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00263078
  • Record Type: Publication
  • Source Agency: Highway Safety Research Institute
  • Files: TRIS
  • Created Date: Nov 20 1977 12:00AM