Closed-Course Study of Driver Detection of Pedestrians beyond Flashing Beacons within Sign Assembly

Abstract

This study evaluated the effect of yellow rapid flashing beacon characteristics on the ability to detect objects located behind a sign during a closed-course driving study sponsored by FHWA. For the analysis focusing on object detection distance, the results indicated that certain study assemblies were associated with shorter object detection distances. During the day, the object detection distance was shorter for objects behind an assembly with two rectangular beacons below the sign (R-B), as opposed to other beacon arrangements, such as two rectangular beacons above the sign and two circular beacons below or above the sign. At night, the detection distance to an object was shorter behind an assembly with R-B when compared with an assembly with two 12-in. circular beacons below the sign. These findings indicated that characteristics of the R-B, such as the light intensity or the location of the beacons, might negatively affect the driver's ability to see an object. For the analysis focusing on the accuracy of detecting objects, which considered the number of objects missed by the participants, the location of the beacons (above or below the sign) was significant during the day but not at night. During the day, participants were less likely to miss an object when the beacons were above the sign.

Comparison of Rectangular and Circular Rapid-Flashing Beacons in an Open-Road Setting

“…A closed-course study conducted for FHWA investigated driver ability to detect an object (e.g., box, trash can, pedestrian) about 3 ft beyond an assembly for different combinations of beacon shape (i.e., circular or rectangular), size (i.e., 8 or 12 in. for the circular shape), and placement (i.e., above or below the flashing sign) (5). The study showed that certain assemblies were associated with shorter object-detection distances, which are not desirable.…”

“…Toward the conclusion of the closed-course study, cities were sought to participate in the open-road research; city representatives were contacted and requests were made at professional society meetings (5). Four cities volunteered to participate: Milwaukee, Wisconsin; Flagstaff, Arizona; Austin, Texas; and College Station, Texas.…”

“…circular beacon located below the sign. It was shown to enable longer sign legibility distances at night, and longer object-detection distances both day and night than other assemblies (5).…”