A study of the effects of road tunnel on driver behavior and road safety using driving simulator

The present paper wants to contribute to the knowledge of the tunnel effects on driving performance and safety using the advanced technology of driving simulator. Specifically this study presents the first results of a wider research aimed at establishing how drivers behave inside road tunnel as well as approaching it and exiting from it. Moreover the study verifies a correlation between accident rates and an advanced indicator of simulation computed inside tunnel sections. A highway scenario with eight existing tunnels is reproduced in CRISS driving simulator and several driving parameters are recorded among a sample of twenty-five drivers. Tunnel scenario (TS) data are processed and compared with those of a control scenario (CS), characterized by the same road geometries and alignment of the first one, but without any tunnels. Results confirm previous findings of naturalistic and simulator driving studies about drivers performance inside road tunnels, with significant differences of longitudinal speeds, acceleration and lateral position recorded along the TS and the CS. Moreover the literature safety indicator of driving simulation Pathologic Discomfort (PD) is computed in order to 1) assess the length of approaching and exiting sections of road tunnel and 2) verify PD correlation with the accident rate recorded inside each tunnel. Simulator limitations and future directions of the research are discussed in order to provide guidelines for practical application to road tunnel design and safety measures, taking in account driving performance.