Abstract: In order to analyze the visual load characteristics of different models and regions in lowgrade highway optical long tunnels, 22 drivers (12 car drivers and 10 truck drivers) are selected for real vehicle experiments of lowgrade highway optical long tunnel by taking Xiyi Tunnel in Yunnan province for example. The pupil area data of the drivers are collected by eye tracker; the significant differences of car and truck drivers at the entrance and exit section are tested by using twoway analysis of variance; the overall variation of drivers′pupil area varying rate is analyzed; and the adaptability of drivers is reflected by coefficient of variation. The results show that: (1) There is a significant difference in the average rate of variation in pupil area between the entrance and exit sections of the tunnel and the drivers of the car and the truck; and there is no interaction between the two factors in the tunnel area in terms of the rate of variation in pupil area. (2) The visual load of the truck driver in the tunnel is more serious, and increase and decrease of the peak rate of the pupil area in tunnel is greater than that of the car driver. (3) The truck model and the exit area are more sensitive to the visual environment for the driver in the highway tunnel; and the drivers of different vehicle types and different tunnel areas have significant differences in terms of the variation coefficient of the pupil area varying rate.

Key words: highway tunnel, lowgrade highway, optical long tunnel, pupil area, visual load