Vehicle-pedestrian conflicts were reduced by 89 percent in the first half of the crossing and 43 percent in the second half with automated pedestrian detection at intersections in Los Angeles, California; Rochester, New York; and Phoenix, Arizona.
Date Posted
01/01/2000
Identifier
2000-B00018
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ITS and Pedestrian Safety at Signalized Intersections

Summary Information

ITS applied to pedestrian safety is often overlooked when discussing benefits of ITS. Automated detection technology can be applied to pedestrian crosswalks. These systems can be used to augment the traditional push button technology to alert signals of the presence of a pedestrian waiting to cross intersections. In addition they can be used to detect the presence of pedestrians remaining in crosswalks during signal phase changes. The systems can be used to reduce vehicle and pedestrian conflicts by adapting WALK/DON'T WALK signals. The systems adust phase splits to permit slower moving persons to safely cross the intersections and can use a variety of detection technologies including infrared or microwave-based sensors.



Three sites in the United States were used to compare reductions in vehicle and pedestrian conflicts at intersections between push-button activated crosswalk signals, and push-button with automated detection. The three sites were Los Angeles, Rochester NY, and Phoenix. Overall, there was an 81 percent decrease in the number of pedestrians crossing during a DON'T WALK with the addition of automated detection to intersections with operational push buttons. Conflicts encountered by pedestrians during the first half of the crossing were reduced 89 percent while conflicts for the second half were reduced 42 percent. Conflicts associated with right turning vehicle were reduced 40 percent. All other conflicts were reduced 76 percent. Most of these reductions are attributed to reliable detection and signal extension for pedestrians in the process of crossing, not those waiting at the curb to cross.



Additional data were collected at the Los Angeles site with the intent to evaluate pedestrian perceptions when the push-button was taped-over (i.e. automated detection only) just after the automated detection system was initially installed. The results indicated that when the button was taped-over, pedestrians were five times more likely to begin crossing during the displayed DON'T WALK phase compared to the period when the manual push-button and detection system were both present and functioning. The author attributed this behavior to pedestrian perceptions that the system was unreliable when the push-button was taped over, even though appropriate WALK, flashing DON'T WALK, and steady DON'T WALK signals were displayed.

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