Aiming at solving the problem of driver's visual adaptation caused by frequent changes of light environment in mountainous highway tunnel group, this paper proposes a tunnel awning design method that effectively saves tunnel operating costs and improves driving safety.Through theoretical analysis, the relationship between two tunnel spacing D and the economic benefit rate when using the awning is established.The effect of the awning effect was simulated and analyzed by using DIAlux lighting simulation software, The light transmittance of the awning at the connecting tunnel was obtained as a function of the tunnel design speed and traffic flow.Taking an adjacent tunnel in Yunnan as an example, when the awning design method is adopted, the tunnel section can save about 15% of the lighting cost every year, and the visual obstacles when the driver enters and exits the tunnel are effectively improved. Research methods and results have reference value for the setting and operation of highway tunnel lighting.

CICTP