The study primarily intended to evaluate the operational and safety impacts of pedestrian hybrid beacons (PHBs) on Arizona state highways (higher-speed roads) to understand their impacts on vehicles and pedestrians. The study investigated the relationship between crashes at PHB locations and two variables: 1) the spacing from nearby signalized intersections, and 2) other roadway characteristics. PHB indications are as follows: dark, flashing yellow, steady yellow, steady red, and alternating flashing red. A total of 10 sites (all with speed limits of 45 or 50 mi/h) with 822 PHB locations were evaluated. Sites were located throughout Arizona in Bullhead City, Scottsdale, Phoenix, Tempe, Gilbert, Tucson, Sierra Vista, and Pima County. An operational analysis assessed PHB effectiveness on higher-speed streets with an observation study. A total of 1,214 pedestrians and bicyclists were observed between April 25 and May 8, 2018; 40 hours of video data of each site were manually evaluated. A safety evaluation assessed a total of 343 sites (186 PHBs, 56 signalized intersections, and 101 unsignalized intersections).
Researchers conducted a statistical before-after study based on Empirical Bayes (EB) and Safety Performance Functions (SPFs) to analyze safety effectiveness. The observed crash frequency after the installation of the PHB was compared to the expected crash frequency without the PHB. The following measures were included in the EB study: the percentage of drivers yielding to pedestrians during a steady or flashing red, the number of drivers who did not stop during a steady or flashing red, the percentage of pedestrians using the push-button, and the percentage of pedestrians crossing the roadway by PHB indications. The following crash types were included: total number of crashes; and fatal and injury (FI), rear-end, angle, pedestrian-related, FI rear-end, FI angle, and FI pedestrian-related crashes. Researchers also documented driver stop compliance, driver yield behavior, pedestrian behavior, and pedestrian-vehicle conflicts during manual evaluation.
This study identified the following safety benefits with the installation of PHBs:
- For the 52 PHB sites included in the EB before-after study using unsignalized intersections and signalized intersections as a reference group, the percentage of pedestrian-related crashes decreased by 46 percent.
- The total number of crashes was reduced by 18 percent. Rear-end crashes decreased by 21 percent and angle crashes decreased by 23 percent.
- For severe crashes, the total number of FI crashes decreased by 25 percent. FI pedestrian crashes were reduced by 45 percent, FI rear-end crashes by 29 percent, and FI angle crashes by 25 percent.
- Driver yielding to pedestrian ranged from 95 to 100 percent, averaging to 97 percent for the 10 high-speed road sites. For the traffic control device, about 90 percent of drivers complied with the steady red indication while only 41 percent complied with the flashing red indication.
- When the hourly volume of both road approaches was larger than 1,500 vehicles per hour, at least 90 percent of pedestrians activated the PHB.