North Carolina has been a leader in implementation of flashing yellow arrows (FYA) for left turning permissive movements. The public acceptance of such devices has resulted in the implementation of FYA for right turns at intersections with high pedestrian volumes. In addition to this, there are existing sites where Leading Pedestrian Intervals (LPI) have been deployed. LPIs allow pedestrians to enter the street before concurrent vehicular movements are given a green indication.
This report provides data from 10 RT FYA and 14 LPI stand-alone treatment locations across NC. No data were able to be captured at sites with the combination of both treatments at the time of closing the project. Data were only collected at sites following installation as there were no new installations to capture before and after data. For this reason, the project was closed early as nearby sites posed problems to capture surrogate data to represent the before data condition.
Even so, the data captured from both stand-alone treatments following construction offer some potential insights. On first glance, LPI's seem to provide better yielding to pedestrians compared to RT FYA's, with yield rates of 84% compared to 49%, respectively. However, as this study indicates, there may be inherent flaws when comparing the yield rates based on location and staged versus naturalistic crossings. Second, although sample sizes were relatively small, there appeared to be no difference in yield rates when comparing single and dual lane configurations where multiple-threat situations may present dangerous conflicts. Last, observations from the field indicated that most conflicts and violations were the result of vehicles turning right-turn-on-red. As such, the research team believes the use of “blank out" signs in lieu of static signage could help encourage more yielding to pedestrians when the push button is activated. However, given the limited studies of such signs, they should be studied carefully to determine the effectiveness of the additional treatment.
