The City of San Diego conducted a study on the issue in the 1970s, and the report conclusions are often cited as the first comprehensive study of crosswalk safety. Investigators in San Diego observed over 400 intersections during a five-year study period. The results demonstrated that during the five-year period, 177 pedestrians were hit in 400 marked crosswalks compared to 31 pedestrians hit in 400 corresponding unmarked crosswalks.
The study reported that "...more pedestrian accidents occur in marked crosswalks than in unmarked crosswalks by a ratio of approximately 6:1. Furthermore, comparison of the volume of pedestrians using the marked and unmarked crosswalks shows that the crosswalk use ratio is approximately 3:1. This indicates, in terms of usage, that approximately two times as many pedestrian accidents occur in marked crosswalks as compared with unmarked crosswalks. Evidence suggests that this poor accident record is not due to the crosswalk being marked as much as it is a reflection on the pedestrians' attitude and behavior when using the marked crosswalk..."
River Falls Crosswalk Policy Summary
Safety Effects of Marked vs. Unmarked Crosswalks at Uncontrolled Intersections
Wisconsin Pedestrian Traffic Safety Facts