Driving behaviour in smoke - A comparative study between Sweden and New Zealand

This thesis investigated how driving is affected by low visibility due to wildfire smoke. Virtual reality experiments with a driving simulator were performed with 89 participants. The software and hardware configuration mirrored the experiments by Rohaert et al. (2025) in order to compare the results. Participants drove five scenarios with different levels of smoke and were instructed to behave as they would in real life. Main findings were that the free-flow speed was reduced with a decrease in visibility, distance headway was increased with an increase in speed, and an increase in traffic density reduced speed. This is in line with Rohaert et al. (2025). Furthermore, it was concluded that there was no statistical evidence that cultural differences (between participants reported nationality/citizenship divided into continents), familiarity with driving in New Zealand and risk perception had an impact on free-flow speed. Additionally, it was established that gender had an impact on risk perception. Although there was no statistical evidence that gender affected free-flow speed. For driving experience, more specifically, driving habits and years of obtaining a driver’s license, no statistical evidence was shown regarding the impact on the free-flow speed. Although a trend could be noticed that people driving more rarely tend to drive slower. Moreover, familiarity with driving in low visibility was shown not to have an impact on the free-flow speed. Although the findings in this thesis have limitations.