The Science Behind Yellow Rectangular Rapid Flashing Beacons

Drivers often fail to yield to pedestrians who have the right-of-way in marked crosswalks at uncontrolled locations. From the beginning of 2004 to the end of 2006, there were a total of 14,351 pedestrian fatalities and 212,786 pedestrian injuries resulting from pedestrian-automobile collisions nationwide.  Decreasing the occurrence of these crashes would increase the safety and overall walking experience for pedestrians. Anything less than a traffic signal has historically failed to produce over 70 percent yielding at crosswalks on multilane roads. 

Several techniques and technologies have been used to increase driver yielding to pedestrians at marked crosswalks. One older technology included the use of flashing overhead standard yellow beacons. 

More recent approaches include the use of in-street signs labeled “YIELD TO PEDESTRIAN” and in-roadway lights. Ellis et al. experimented with in-street signs placed vertically in center lanes. The signs were placed at the crossing, 20 ft in advance of the crosswalk, and 40 ft in advance of the crosswalk.

The installation of these signs produced an increase of two to three times the yielding percentage over the baseline, with maximum yielding of about 61%. However, a study by Turner et al. shows that in-street signs do not work well on multilane roads. Several studies have shown only modest increases in yielding with in-pavement lighting.

One possible explanation of why the RRFB system produced a larger increase in driver yielding over the baseline is that it produced a novelty effect where an unfamiliar stimulus that had not been encountered by the drivers in the past was more likely to get their attention (similar to an unusual sound getting someone’s attention). If this was the case, there should be a large decrease in yielding behavior over time; however, this was not found. The follow-up data showed that the systems were still associated with high yielding behavior 1 and 2 years after installation. It appears that the lights on the system were such a salient stimulus that they obtained drivers’ attention over the other competing stimuli and distractions they were exposed to when driving. 

(Report No. FHWA-HRT-10-043)