High Ambient Temperatures and Risk of Motor Vehicle Crashes in Catalonia, Spain (2000–2011): A Time-Series Analysis

http://dx.doi.org/10.1289/ehp.1409223



Table 4. Association between temperature and daily number of motor vehicle crashes stratified by period.
Strata All crashes Crashes with driver performance–associated factorsa
Percent differenceb (95% CI) p-Value Percent differenceb (95% CI) p-Value
aCrashes that included among the list of concurrent factors at least one of the following: “distraction,” “driver error,” or “disease, fatigue, or sleepiness.” bPercent difference in risk of crashes (with 95% CIs) obtained from a meta-analysis of climatic zone–specific results. Models were adjusted for precipitation, day of the week, holidays, days at the beginning or end of a holiday period, and a strata variable uniquely identifying all combinations of year and month. Models for crashes with driver performance–associated factors were further adjusted for the daily number of motor vehicle crashes with factors unrelated to driver performance. cHeat waves were defined as ≥ 2 consecutive days with maximum temperature exceeding the weather station–specific historic 95th percentile.
2000–2003
Maximum temperature (°C) –0.1 (–1.1, 0.9) 0.803 0.4 (–0.5, 1.3) 0.337
Heat wave day (tmax)c (yes/no) 0.9 (–3.2, 5.1) 0.676 6.6 (–4.2, 18.6) 0.241
2004–2007
Maximum temperature (°C) 0.3 (–0.7, 1.2) 0.561 0.8 (0.0, 1.6) 0.052
Heat wave day (tmax)c (yes/no) 3.4 (–0.8, 7.8) 0.136 8.9 (1.1, 17.3) 0.025
2008–2011
Maximum temperature (°C) 0.8 (0.3, 1.3) 0.005 1.6 (0.1, 3.2) 0.039
Heat wave day (tmax)c (yes/no) 4.7 (0.8, 8.8) 0.018 7.8 (–3.4, 20.3) 0.182