The objective of this research was to analyse driver behaviour and comprehension related to the Flashing Yellow Arrow (FYA) permissive left-turn indication when added to three- and five-section traffic signal displays. FYA indications were evaluated bimodally with both the Green Arrow (GA) and Yellow Arrow (YA) indications and compared with the recommended four-section vertical all arrow signal display. Findings from a computer-based static study showed no significant differences in driver comprehension when the FYA indication was presented bimodally in the bottom section or middle section of a three-section vertical signal display. However, driver comprehension was significantly lower when the FYA indication was added bimodally to the five-section cluster signal display with a simultaneous thru movement indication illuminated. Results of a full-scale driving simulator evaluation showed no significant differences in driver performance or vehicle operation between the evaluated traffic signal display combinations. Driver eye tracking data showed that participants spent considerably more time looking at opposing traffic than at the combination of FYA and thru movement indications. Research results support the recommendation that the FYA permissive left-turn indication can be effectively implemented bimodally with the YA indication in a three-section vertical signal display, but not bimodally with the GA or in any five-section cluster signal display. (Author/publisher)
Samenvatting