Light and Dark Adaption Times Based on Pupil Area Variation at Entrance and Exit Areas of Highway Tunnels

Abstract

The sharp variation of illumination at the entrance and exit of highway tunnels causes difficulty in the visual adaptation of drivers and may even lead to accidents. Therefore, ascertaining the light and dark adaption time is a basic task to promote the safety of tunnel transportation. Took 26 typical tunnels as experimental settings and used the IViewX HED Laptop eye tracker system, the light and dark adaption of drivers in highway tunnels had been experimentally investigated. The relation between pupil area and its variation velocity was presented based on many experimental data and the ratio k of the variation velocity to its critical variation velocity was used to evaluate the visual load in highway tunnels and thus ascertained the visual adaption time, whereby the relation between tunnel length and visual adaptation time was thus obtained. Experimental results indicated that the dark and light adaption time of tunnels was less than 23 s and 13 s for medium and long length tunnels, respectively.