Experimental attempt on walking behavior and stress assessment in a completely darkened tunnel

Abstract

In case of massive fire incidents in tunnels, ceiling lights are covered by dense smoke, and pedestrians must evacuate in the dark tunnel with almost zero visibility. Nonetheless, the walking behavior in a completely darkened tunnel has not been clarified. In this study, we experimentally attempted to investigate the evacuation loci and assess the stress of evacuees by measuring oxytocin and cortisol concentrations in saliva, heart rates, blood pressures, and responses in a survey questionnaire for a full-scale tunnel. Results indicated few differences in both one-and two-dimensional walking speed. In terms of stress, the group of subjects who felt stress demonstrated a walking speed that is 0.17 m/s slower than the group that did not feel it. In the questionnaire survey, most of the subjects answered that the wall was the most helpful item, followed by the unevenness (bumps) on the white lines on the road. One of the subjects became lost, stating that she could not find the unevenness (bumps) on the white lines. These two factors can be rational guides in a dense smoke environment or a completely dark tunnel scenario.