Traffic control devices, such as rectangular rapid-flashing beacons (RRFBs), have been shown to increase the number of drivers yielding to crossing pedestrians. Evaluations of field installations of these devices have been conducted in several locations, including Florida, Texas, Oregon, Michigan, Arizona, Wisconsin, and Calgary, AB. Before-after studies have shown a large increase in driver yielding between the before period (range of 1 to 83 percent) to the after period (range of 38 to 98 percent). Although the RRFB is allowed under interim approval from the Federal Highway Administration (FHWA), there is a growing interest in adding it to the Manual on Uniform Traffic Control Devices (MUTCD). The Signals Technical Committee (STC) of the National Committee on Uniform Traffic Control Devices, which assists in developing language for chapter 4 of the MUTCD, is interested in research and/or assistance in developing materials on the design, application, and effectiveness of the RRFB. One of the areas for which the STC is seeking advice is the position of the beacons relative to the crossing sign. For example, does positioning the beacons above the sign improve the driver’s ability to see a pedestrian crossing or waiting to cross and thus yield to crossing pedestrians? This TechBrief describes the methodology and results from an open-road study sponsored by FHWA that examined driver yielding behaviour at crosswalks with RRFBs positioned above the pedestrian crossing sign and at crosswalks with RRFBs positioned below the sign. On July 16, 2008, FHWA issued Interim Approval 11 (IA-11) for the optional use of the RRFB at uncontrolled pedestrian and school crosswalks. As defined in IA-11, the RRFB shall consist of two rapidly and alternately flashing rectangular yellow indications that have light emitting diode array-based pulsing light sources. When IA-11 was issued, the only position for the beacons in the pedestrian sign assembly was between the crossing warning sign and the supplemental plaque. IA-11 describes the position as a specific exception to the then-current 2003 MUTCD section 4K.01 guidance, stating that the RRFB shall be located between the bottom of the crossing warning sign and the top of the supplemental downward diagonal arrow plaque (or, in the case of a supplemental advance sign, the AHEAD plaque), rather than 12 inches above or below the sign assembly. The objective of this study was to determine benefits of different positions for the RRFBs being used with pedestrian or school crossing signs. The study included both a closed-course and an open-road portion. This TechBrief is focused on the open-road study. Details on the closed-course study are available in another TechBrief. Because the closed-course study indicated that benefits may exist for placing the beacons above the sign, the open-road study investigated whether drivers yield differently to RRFBs placed above the pedestrian crossing sign instead of below the pedestrian crossing sign. This study measured the percentage of drivers yielding to crossing pedestrians at the same pedestrian crosswalk when the beacons were located above the crossing warning signs and when the beacons were located below the crossing warning signs. (Author/publisher)
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