Exploring the relationship of rush hour period and fatal and non-fatal crash injuries in the U.S.: A systematic review and meta-analysis.

ABSTRACT

Road crashes are preventable causes of morbidity and mortality. In the U.S., substantial crashes occur during the rush hour period. The rush hour represents the period of the day during which the density of humans and vehicles in the road environment is highest. In the U.S., the rush hour period is bi-modal, occurring in the morning and the afternoon, at times that vary by state and urban-rural status. This systematic review and meta-analysis aimed to evaluate the association between the rush hour period and fatal and non-fatal crash injuries. Selected articles were limited to peer-reviewed full-text articles that measured crash injury as an outcome and rush hour as either a predictor, covariate, stratification, or a control variable. A total of 17 articles were identified for systematic review and nine articles were included in the meta-analysis. Across the selected studies, the rush-hour period signified the period of "peak traffic flow." During the rush hour period, aggressive driving behavior, truck driving, bicycle riding, and precipitation were associated with increased crash events or crash injuries. Across the nine studies included in the meta-analysis, the effective sample size was 236,433. The rush-hour period was associated with a 28% increased risk of fatal crash injury (Pooled RR 1.28; 95% CI 1.11-1.45) and the morning rush hour period was associated with 36% increased crash injury risk (Pooled RR 1.36; 95% CI 1.13-1.59). The rush hour period, though less commonly studied as a predictor of fatal and non-fatal crash injuries, represents an important domain in need of crash injury prevention attention. The knowledge of the pattern of crash injuries, as it varies across countries, states, regions, and county can inform policy and intervention, in the presence of competing public health needs.