In Spring 2010, the Illinois Department of Transportation initiated an areawide implementation of the flashing yellow arrow (FYA) as the display for the left-turn permissive interval at more than 100 intersections operating with protected/permissive left-turn (PPLT) control in the Peoria, Illinois, area. Bradley University researchers evaluated the effectiveness of FYAs on driver comprehension and traffic operations. A total of 363 drivers completed an online static survey that included seven left-turn scenarios that portrayed the protected and permissive indications of PPLT phasing, with the flashing modes being animated. The results of the survey indicated that drivers had a high comprehension of both the circular green (CG) and FYA permissive left-turn indications. However, the survey results provided evidence of some drivers’ misinterpreting the meaning of a permissive left-turn with CG display and incorrectly and unsafely interpreting the meaning as “go” under some circumstances. With supplemental traffic signs present, drivers’ understanding of the correct action to take when confronted with a FYA significantly increased, and the percentage of fail-critical, incorrect “go” responses significantly decreased. Before and after field observations, including 128 hours of data collected at 16 study approaches, were collected; and the following variables were investigated: critical gap, left-turn red-light running and yellow-light running, and traffic conflicts. Overall, the findings of this study suggest that drivers in the Peoria, Illinois, area had high comprehension and acceptance of the FYA message. Additionally, the FYA did not appear to have any negative impacts on traffic operations. (Author/publisher)
Samenvatting