Impact of Tunnel Groups on Pupil Diameter of Drivers on Mountainous Freeway in China: A Real-World Driving Study

Jianping Gao,Yi Wu,Yunyong He,Enhuai He,Chang Lu,Sijie Zhang,Qi Zhang,Lu Sun,Changfeng Yang,Jaeyoung Lee

doi:10.1155/2021/5629536

Abstract

A real-world driving experiment was performed in the Wen-Ma section of the G4217 Rong-Chang Freeway situated in the Sichuan Province to investigate the impact law of the pupil diameter of drivers in tunnel groups on the mountainous freeway. The eye-movement data of drivers were collected, and the percentage of pupil diameter variable (PPDV) was used as a visual characteristic index. The analysis of the overall change in the PPDV of drivers in the experimental sections demonstrated that the PPDV in tunnel groups differed significantly between the nontunnel sections and single tunnel sections. Subsequently, a related model for the PPDV of drivers and the length of the connecting zone between tunnels was established, its reliability evaluated, and the smooth mutation value obtained on the basis of the mutation theory. Thereafter, a tunnel group definition standard based on the visual effect of drivers was developed. A six-zone approach was devised for the analysis of tunnel groups, and the result revealed that the different zones in the tunnel group have different impact on PPDV of drivers. The results revealed that the different zones of tunnel group have different impact on PPDV of drivers. Furthermore, lighting transition facilities should be set in the exit section of tunnel. The PPDV of drivers was negatively correlated with the length of the connecting zone of tunnel groups, and 100 m is the recommended safety length threshold for the connecting zone of tunnel groups.

Highlights

With the expansion of Chinese freeways to remote mountainous areas, the extent of mountainous freeways has considerably increased
Data. e pupil diameters of the three drivers in the static state were measured, and the arithmetic mean value was used as the reference value for the pupil diameter. e pupil diameter variable (PPDV) was calculated according to equations (1) and (2), and the mean value was taken as the feature point every 1 s
E test results demonstrated that the PPDV in the nontunnel and continuous tunnel sections approximately conformed to a normal distribution, whereas the PPDV in the single tunnel section conformed to a normal distribution at α 0.05 . e Grubbs test method was used to screen and eliminate the outliers of the PPDV in the three sections; the results for the nontunnel sections are shown in Figure 3. is test method is suitable for upper, lower, and bilateral cases

Summary

Introduction

With the expansion of Chinese freeways to remote mountainous areas, the extent of mountainous freeways has considerably increased. The proportion of tunnel sections on mountainous freeways has been increasing, which has led to the emergence of dangerous sections such as continuous tunnels or even multitunnel group sections [1]. Drivers enter and exit tunnels several times in a short time, and the frequent changes in the illumination intensity lead to a repeated visual adaptation process between light and dark illuminations for drivers. It results in “black and white hole” effects and the deterioration of drivers’ visibility. Zhao et al [3, 6] found that the visibility and vehicle speeds inside a tunnel were significantly different from those of single tunnel and tunnel group sections

Methods

Results

Conclusion