PREFERENCES FOR PERMITTED AND PROTECTED LEFT-TURN SIGNAL DISPLAYS

Twenty-two different signal displays for permitted and protected left turns were evaluated from a driver comprehension perspective. The objective was to identify which alternate signal displays used to convey the same left-turn message to the driver are better comprehended and therefore recommended for use in the field. Protected displays compliant with the Manual on Uniform Traffic Control Devices (MUTCD) were found to be better comprehended than certain noncompliant displays; however, some noncompliant permitted displays were found to outperform their compliant counterparts. Regional comprehension biases are nonexistent for the most part, regardless of display compliance with the MUTCD. Permitted left-turn signals using indications other than a steady green ball were found to enhance driver comprehension. The "Left Turn Must Yield on Green Ball" sign used with a "doghouse" display is beneficial during the permitted phase, but confusing when displayed during the protected left-and-through phase. Other supplemental signs used with various left-turn displays were also evaluated.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/8674831
• Corporate Authors:

  American Society of Civil Engineers

  1801 Alexander Bell Drive
  Reston, VA  United States  20191-4400
• Authors:
  • Drakopoulos, A
  • Lyles, Richard W
• Publication Date: 2000-5

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: p. 202-211
• Serial:
  • Journal of Transportation Engineering
  • Volume: 126
  • Issue Number: 3
  • Publisher: American Society of Civil Engineers
  • ISSN: 0733-947X
  • Serial URL: https://ascelibrary.org/journal/jtepbs

Subject/Index Terms

• TRT Terms: Compliance; Comprehension; Drivers; Error analysis; Evaluation; Green interval (Traffic signal cycle); Human factors engineering; Left turns; Regional analysis; Safety; Traffic signals; Traffic signs
• Identifier Terms: Manual on Uniform Traffic Control Devices
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I85: Safety Devices used in Transport Infrastructure;

Filing Info

• Accession Number: 00794108
• Record Type: Publication
• Contract Numbers: V-406
• Files: TRIS, ATRI
• Created Date: Jun 26 2000 12:00AM