This paper presents the accident reduction effect found by installing roadway lighting in conformance with the american national standard practice for roadway lighting. A portion of ogden avenue in naperville, illinois, had only one block of modern lighting plus a fewintersection lights in a length of 2.8 Km. This five-lane roadway (two through lanes plus a center two-way left-turn lane) is 18 m wide. Street lighting was installed and maintained at a design level of 15 lux, as appropriate for a major route in an intermediate area. A 4-year study of accidents was made, with 1984 and 1985 used in the "before" period and 1986 and 1987 in the "after" period. More than 800 accidents occurred during the total study period. Overall, accidents were reduced from 31% at night to 23% in the "after" period. The greatest reduction was in midblock locations, where the "before" percentage was 35 and the "after" was 21. The night accident reduction was 36%, calculated either on a night/day ratio of rates per millionvehicle kilometers or by the simpler method of night percent change. If total day plus night accidents are considered, the overall accident reduction was 14%. An economic analysis, comparing the installation cost with the estimated cost of accidents prevented, showed payback in one year. This paper appears in transportation research record no. 1247, Visibility criteria for signs, signals, and roadway lighting.
Samenvatting