Research On Disability Glare Evaluation Index Limit Of Different Types Of Overpasses With High Mast Lighting

This paper is the third stage of the 2012 National Natural Science Foundation Project “Study on the Safety Lighting of City Overpass Based on High Dynamic Range Image”(Project Number:51178299). Urban overpass often use high mast lamp to deal with night traffic problems. Its multi-level structures allow multi-direction traffic, so it is important to ease urban traffic pressure. But domestic and foreign still lacks of research on disability glare of overpass lighting. This article put forward the evaluation index of disability glare of overpass lighting on domestic, which is significant for safe driving at night of overpass road.Through statistics of overpass types in different places, it can be drawn that the most three typical types of overpasses were separated interchange, cloverleaf interchange and semi directional interchange. Through field research, computer simulation and subjective evaluation, this paper determined the most suitable disability glare evaluation index of each part of the overpass road were threshold increment(TI) and glare rating(GR).The field research selected 8 cities which have a large number of overpasses, such as Tianjin, Beijing, Wuhan, Handan, Zhengzhou, Chongqing, Chengdu and Shanghai. By using high dynamic range image techmology, researchers measure 34 test points of 17 overpasses in these 8 cities, and then calculate TI and GR value of every test point.By using DIALux lighting design software, this article make a simulation aimed at the semi directional interchange, combined with the upper stage achievement, we basically completed the parameter model of three typical forms of overpass. The simulation results show that in the premise of satisfying the overpass road lighting standard, TI and GR values were greater than the ordinary road standard value.According to the situation that TI and GR values are generally higher than the ordinary road standard value, this paper adopts the semantic differential method based on 34 measured overpass high mast lighting scene for subjective evaluation research. The research results shown that TI and GR were highly correlated with subjective evaluation of disability glare feeling, it is said that the increment threshold and glare rating can be used as the overpass road disability glare evaluation index. TI is more suitable to evaluate main road and overline, while GR is more suitable for the ramp of overpass.