Too Hot to Haul? The Impact of Temperature on Labor Supply and Performance of Truck Drivers

This paper studies the effects of extreme temperatures on labor supply and performance in the heavy-duty trucking industry, a pivotal sector with broad productivity spillovers and significant road safety externalities. Using rich and high-frequency data on individual truck drivers in China, we find that exposure to extreme heat significantly reduces labor supply and increases the incidence of risky driving. Evidence further suggests that extreme temperatures disrupt off-duty rest and increase on-duty fatigue among drivers. We also document behavioral adaptation: drivers respond to heat by adjusting work schedules and reallocating labor to adjacent days. Furthermore, the estimated temperature effects on labor supply and risky driving are smaller among drivers employed by firms that offer heat subsidies.