Effects of ambient temperature on drivers’ speed-selective behavior at different risk levels: A driving simulation study

Abstract

Abnormal or inappropriate ambient conditions can lead to reduced driving performance or even crashes, and the ambient temperature could be the most critical and fundamental factor. However, the coupling effects of the ambient temperature and the road and traffic conditions on basic speed-selection behavior are rarely investigated. To this end, this study attempted to evaluate drivers’ speed-selective behavior at low-medium-high risk levels under the low (16 °C ± 2 °C), medium (26 °C ± 2 °C), and high (36 °C ± 2 °C) ambient temperature ranges. To achieve this, a series of driving simulation experiments were conducted with 45 participants. Results showed that, at the low-risk level, the limitations of low-temperature or high-temperature conditions resulted in higher average speed than the medium-temperature condition. At the medium-risk level, the driver’s dynamic speed adjustment behavior was degraded under low-temperature or high-temperature conditions, and the deceleration rate was higher than the medium-temperature condition. At the high-risk level, drivers failed to diminish their speed in a timely way under low-temperature or high-temperature conditions, increasing the risk of crashes. However, decreasing the speed at the point of conflict could be effective in reducing the severity of the collision. The findings of this study can be applied to autonomous vehicles (AVs) to search for better safety countermeasures.