Correlating the Safety Performance of Urban Arterials with Lighting

Abstract

This paper presents a new method to evaluate roadway lighting performance at the corridor level based on the illuminance data collected by a mobile lighting measurement system. The illuminance data were collected at 40 ft (12 m) intervals on the outside and inside lanes for both directions of the roadway. Statistical analysis results indicate that the illuminance data at the corridor level fit the lognormal distribution. Two parameters, the mean and the variance of the illuminance, could be used to evaluate the lighting system at the corridor level by comparing the parameters for the roadway lighting systems with those for the design standard. In addition, the daytime and nighttime crash rates for the study corridors were calculated. The results indicate that the illuminance parameters are significantly related with the difference between daytime and nighttime crash rates; this factor further justifies the reasonableness of the new lighting evaluation method. The proposed method is recommended for evaluating lighting systems at the corridor level when the data are collected with the new mobile lighting measurement system.