Figure 1

Reported incidence of drowsy driving and motor vehicle crashes associated with sleep duration in the 24-hour period prior to driving among truck drivers [18]. Data are odds ratios (ORs) adjusted for major confounding factors. Error bars represent 95% confidence intervals (CIs). For the motor vehicle crashes, the upper 95% CI was 6.61 in the < 5-hour sleep, 9.68 in the 5-hour sleep, and 5.83 in the ≥ 9-hour sleep groups.