Evacuation behaviour under smoke conditions in a real-scale road tunnel experiment in Poland

Abstract Road tunnel fires pose a serious safety challenge because smoke, reduced visibility and limited escape options can strongly affect evacuation behaviour. This study presents a real-scale evacuation experiment conducted in the road tunnel under the Dead Vistula River in Gdańsk, Poland. Participants entered the tunnel in a city bus, which stopped in a smoke-filled tunnel tube, after which an emergency scenario was initiated and tunnel safety systems were activated. The analysis combined chip-based time measurements, movement observations and post-experiment questionnaires from two evacuation trials. The total evacuation time was similar in both trials: the last participant completed evacuation after 378 s in Trial 1 and 376 s in Trial 2. Mean total evacuation time also did not differ significantly. However, participants spent significantly less time in the smoke-filled section during Trial 2, with the mean time decreasing from 60.32 ± 18.73 s to 40.09 ± 10.69 s. A dominant route-choice pattern was observed, with most participants selecting E2 in both trials, despite this emergency passage being located farther from the bus. The results show that total evacuation time alone does not fully describe tunnel evacuation performance and should be complemented by staged movement analysis, route-choice data and subjective perception.