Document Type
Article
Language
eng
Publication Date
5-2000
Publisher
American Society of Civil Engineers (ASCE)
Source Publication
Journal of Transportation Engineering
Source ISSN
0733-947X
Abstract
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 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 Manual on Uniform Traffic Control Devices. 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.
Recommended Citation
Drakopoulos, Alexander and Lyles, Richard W., "Preferences for Permitted and Protected Left-Turn Signal Displays" (2000). Civil and Environmental Engineering Faculty Research and Publications. 207.
https://epublications.marquette.edu/civengin_fac/207
Comments
Accepted version. Journal of Transportation Engineering, Vol. 126, No. 3 (May 2000): 202-211. DOI. © 2000 American Society of Civil Engineering. Used with permission.
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