Extreme environmental temperatures and motorcycle crashes: a time-series analysis

Abstract

Extreme temperature could affect traffic crashes by influencing road safety, vehicle performance, and drivers’ behavior and abilities. Studies evaluating the impacts of extreme temperatures on the risk of traffic crashes have mainly overlooked the potential role of vehicle air conditioners. The aim of this study, therefore, was to evaluate the effect of exposure to extreme cold and hot temperatures on seeking medical attention due to motorcycle crashes. The study was conducted in Iran by using medical attendance for motorcycle crashes from March 2011 to June 2017. Data on daily minimum, mean and maximum temperature (°C), relative humidity (%), wind velocity (km/h), and precipitation (mm/day) were collected. We developed semi-parametric generalized additive models following a quasi-Poisson distribution with the distributed nonlinear lag model to estimate the immediate and lagged associations (reported as relative risk [RR], and 95% confidence interval [CI]). Between March 2011 and June 2017, 36,079 medical attendances due to motorcycle road traffic crashes were recorded (15.8 ± 5.92 victims per day). In this time period, the recorded temperature ranged from −11.2 to 45.4 °C (average: 25.5 ± 11.0 °C). We found an increased risk of medical attendance for motorcycle crashes (based on maximum daily temperature) at both extremely cold (1st percentile) and hot (99th percentile) temperatures and also hot (75th percentile) temperatures, mainly during lags 0 to 3 days (e.g., RR: 1.12 [95% CI: 1.05: 1.20]; RR: 1.08 [95% CI: 1.01: 1.16]; RR: 1.20 [95% CI: 1.09: 1.32] at lag0 for extremely cold, hot, and extremely hot conditions, respectively). The risk estimates for extremely hot temperatures were larger than hot and extremely cold temperatures. We estimated that 11.01% (95% CI: 7.77:14.06) of the medical attendance for motorcycle crashes is estimated to be attributable to non-optimal temperature (using mean temperature as exposure variable). Our findings have important public health messaging, given the considerable burden associated with road traffic injury, particularly in low- and middle-income countries.

The effects of ambient temperature on road traffic injuries in Jinan city: a time-stratified case-crossover study based on distributed lag nonlinear model

“…Previous study have shown that high and low temperatures were obviously correlated with RTIs, and the effect of extreme hot weather was significantly higher than that of extreme cold weather ( 27 ), which was consistent with the results of this paper on the impact of high temperatures. Wu et al ( 16 ) showed that there was a significant positive correlation between fatal traffic accidents and heat waves in the United States.…”

Ambient temperature and risk of motor vehicle crashes: A countrywide analysis in Spain

“…In our study, we found elevated risks not only on the same day, but also delayed effects of up to a week. Other studies have also found delayed effects (Hou et al, 2022;Lee et al, 2020;Liang et al, 2021;Zare Sakhvidi et al, 2022). This suggests that the mechanisms leading to those increases in risk are not restricted only to the direct effect of temperature at the time of the crash.…”

“…A study in Pakistan reported an increase in the risk of road fatalities of 3.6% for a 1% increase in temperature (Ali et al, 2020). A study in Iran focused specifically on motorcycle crashes and found a 20% increase in risk when comparing the 99th percentile of temperature with the temperature of minimum crashes (Zare Sakhvidi et al, 2022). Finally, a countrywide study in Italy found increases of 12% and of 6% when comparing the 75th and 99th percentiles of temperature for overall road crashes and work-related road crashes, respectively (Gariazzo et al,Fig.…”

“…They reported results comparing the 25th and first percentiles of temperature, and the first percentile was below 0 • C for many parts of Italy. The study in Iran, that was restricted to motorcycle crashes, reported effects of cold for temperatures above 0 • C (Zare Sakhvidi et al, 2022). The mechanisms leading to increased risk of crashes involving motorcycles may be different than those of drivers of closed vehicles, as motorcycles are directly exposed to ambient temperature.…”

“…The association between temperature and actual crashes can only be assessed in observational studies. Several of them have documented an increased risk of crashes with heat (Ali et al, 2020;Gariazzo et al, 2021;Hou et al, 2022;Lee et al, 2020;Liang et al, 2021;Liu et al, 2017;Nazif-Munoz et al, 2021;Park et al, 2021;Wu et al, 2018;Zare Sakhvidi et al, 2022), and a few of them with cold temperatures (Gariazzo et al, 2021;Hou et al, 2022;Lee et al, 2020;Liang et al, 2021;Zare Sakhvidi et al, 2022).…”