Study On Lighting Optimization Of Expressway Long-tunnel Entrance Section

As freeway tunnels own the special structure of the openings at both ends and the sealingin the midst, it causes the environment in the tunnel is enormously different from outside,especially the mutation of lighting environment in the entrance section of the tunnel, and itmakes serious impact on the vision of drivers to correct cognition for the traffic environment.At present, in the domestic the design and application of lighting also refer to Design Code ofVentilation and Lighting in tunnel, and part of it is importing wholesale the standard andspecification of lighting from abroad. It does not make in-depth theoretical and practicalresearch according to the characteristics of the tunnel in our country and visual adaptation ofthe drivers, also does not have to distinguish between day and night according to differentsituations. So it is easy to influence serious light-dark adaptation of visual problems ofdrivers, and cause serious hidden trouble and waste of energy for traffic safety intunnel.Therefore, the research on the lighting optimization at the entrance section of theexpressway tunnels has important significance for transportation security and energy andemission reduction.The thesis systematically sorts out271typical traffic accidents in expressway tunnels inour country happened in recent years and makes a concrete analysis of these traffic accidentswhich happened in the entrance section of the tunnel according to distribution characteristicsin space and time and the visual light adaptation of drivers in the tunnel. It obtains theexperimental parameters of the program of the lighting optimization based on the mechanismof the visual adaptation and uses the test method of real vehicle experiment at entrance sectionof the tunnel in the south of Wutai Mountain. In the all process it collects the visualcharacteristic parameters of the drivers、the data of their pupil area、the data of the visualadaptation time and the data of illumination. What’s more, it applies statistical methods suchas correlation analysis、regression analysis to get the mathematical model of drivers’ pupilarea changing with the visual adaptation time, it finally obtains the mathematical model ofdrivers’ pupil area changing with the illumination and the visual adaptation time anddetermines the reference value of illumination for the entrance section of the tunnel.According to comparative analysis of the referential illumination after the optimization、the real illumination before the optimization and the illumination prescribed by lightingspecification at entrance section of the tunnel, the conclusions can be drawn as follows: The referential illumination after the optimization in day is lower than that prescribed by lightingspecification and higher than the real illumination before the optimization, so it can meet thecognitive need for the vision of drivers and reduce the impact on the process of darkadaptation of driver; the referential illumination after the optimization in night is obviouslylower than the real illumination before the optimization and much lower than the illuminationprescribed by lighting specification, the referential illumination after the optimization canmeet the visual demand in night at entrance section of the tunnel、reduce the adverse impacton the process of light adaptation of driver、benefit transportation security and contribute toenergy and emission reduction in some degree.This thesis presents the analysis and modeling method of the lighting optimization basedon the needs of visual cognition of drivers at the entrance section in the long tunnel. Itprovides the theoretic foundation and an important reference for follow-up study for thelighting optimization at entrance section of tunnels.