Three- or Four-Section Displays for Permissive Left Turns?
Transportation Research Record
Many jurisdictions are using the flashing yellow arrow (FYA) to control protected/permissive left turns (PPLTs). For cost and other reasons, some jurisdictions have or are considering implementing FYA with a three-section vertical head, displaying the flashing yellow indication in the same signal face as the protected green arrow. The current Manual on Uniform Traffic Control Devices (MUTCD) permits threesection operation only in height-restricted locations for permissive turns. This paper
... rizes the comparison of driver performance with respect to three-and four-section FYA signal configurations gathered in a high-fidelity, motion-based driving simulator with mobile eye-tracking equipment. The experiment controlled for the effects of the opposing traffic, the presence and walking direction of pedestrians, and the signal head arrangement. A 24-intersection simulated environment was created and 27 subjects completed the course, producing 620 permissive left-turn maneuvers for further analysis. Driver performance was measured by 1) average total eye-glance durations at specific areas of interest and 2) the position of the pedestrian in the crosswalk when the driver initiated the left turn. No statistical differences were identified between the average fixation duration when the FYA was presented with a three-or four-section signal head. The pedestrian's position in the crosswalk when the driver began the left turn was not statistically different for three of the four pedestrian walking directions presented. Overall, it would seem that measureable driver performance is not sensitive to the vertical positioning of the FYA display in the permissive interval.