As a means of improving safety at uncontrolled pedestrian crosswalks, the Federal Highway Administration (FHWA) has sponsored research on a variety of traffic control devices intended to increase driver awareness and improve their behavior in yielding to pedestrians, with one of the devices showing positive results.
An FHWA project conducted by the Texas A&M Transportation Institute (TTI) on the use of rectangular rapid-flashing beacons (RRFB) started with a closed-course study at the university’s Riverside Campus that examined driver detection of a cutout pedestrian photograph in the presence of LEDs, with various brightness levels, flash patterns and locations within the sign assembly. The results from the closed-course study indicated that the flash pattern and the beacon location justified additional investigations on the open road.
The research team used a staged pedestrian approach to evaluate drivers’ yielding on the open road. Under this protocol, a member of the research team acts as a pedestrian using the crosswalk to stage the conditions under which driver yielding would be observed. The TTI team developed a temporary light bar and controller that permitted researchers to have control over the flash pattern and brightness. Three flashing light patterns were selected for use with the temporary light bars; the pattern currently being used with other installations, along with two patterns developed by TTI in collaboration with FHWA and other transportation professionals.
The open-road study found that driver yielding is the same whether the beacons are above or below the sign, while the closed-course study revealed there are potential benefits to having the beacon placed above the sign. The overall average driver yielding for each of the three flash patterns was between 78-80% for the eight sites in the study.
The statistical evaluation found no difference in effectiveness between the three patterns. Because the tested flash patterns had similar driver yielding results, the FHWA issued an official interpretation that favors one of the new patterns (called WW+S), because it has a greater percentage of dark time when both beacons of the RRFB are off (a benefit identified in the closed course) and because the beacons are on for less total time, resulting in energy savings. With the closed-course study revealing that there are benefits to having the RRFB above the sign, the FHWA is planning to issue an official interpretation that will allow agencies to place it in that position.
“The RRFB is very effective,” said Kay Fitzpatrick, manager for the TTI’s Roadway Design Program. “A study conducted about 10 years ago found that you had to have a device that showed a red indication for drivers to yield at a high enough rate to be considered acceptable. Now with the RRFB, there is a device with a yellow indication where drivers are yielding at much higher rates. Having this device only active when a pedestrian is present is an obvious contribution to its effectiveness. The FHWA also wanted to investigate on the open road whether drivers would continue to yield at the same rates if the beacon placement was different. The findings from these FHWA studies are helping to refine the device characteristics, resulting in a pedestrian treatment being considered for the next edition of the MUTCD (Manual on Uniform Traffic Control Devices). More importantly, the device is being used in more locations, and drivers are noticing the rapid-flashing yellow beacons and yielding to pedestrians crossing the roadway.”
