In 2002, the City of Oakland, California implemented a scramble signal, at the intersection of 8th Street and Webster Street. Scrambles are a type of traffic signal that give pedestrians exclusive access to an intersection by stopping vehicular traffic on all approaches, allowing pedestrians to cross diagonally or conventionally. The primary objective of this evaluation was to determine whether the installation of the pedestrian scramble at this location increased pedestrian safety. An analysis was conducted of pedestrian-vehicle conflicts and pedestrian violations occurring at the intersection before and after the signal was modified, and pedestrians were surveyed to ascertain public attitude toward and comprehension of the change. The modification to scramble signal phasing at the intersection resulted in a statistically significant decrease in conflicts between pedestrians and vehicles, and a statistically significant increase in pedestrian violations. In general, pedestrians understood the change in the way the intersection operated, and were accepting of the change to scramble signalization. These results suggest that the scramble has been effective overall in improving safety conditions at the site. The increased number of violations occurring despite decreased conflicts is in part due to a proportion of pedestrians who cross illegally on the "safe side" crosswalk (i.e. the crosswalk parallel to moving traffic where there are no opportunities for conflicts). It is important that the scramble signal be monitored over time in order to quantify the extent to which reduced vehicle-pedestrian conflicts associated with the scramble translate into measurable reductions in pedestrian injuries and fatalities.
December 17, 2003