A new study by the AAA Foundation for Traffic Safety indicates that an estimated 17.6% of all fatal crashes from 2017-2021 involved a drowsy driver. Also, over the five-year study period, an estimated 29,834 people were killed in crashes that involved drowsy drivers. The percentage of fatal crashes involving drowsy driving remained approximately constant over the study period; however, the annual number of fatal drowsy driving crashes increased significantly over the study period due to a large increase in total annual fatal crashes.
The National Highway Traffic Safety Administration (NHTSA) states that 91,000 police-reported crashes resulting in 50,000 injuries and 800 fatalities annually — amounting to approximately 1% to 2% of all crashes, injuries and deaths— involve drowsy driving; however, the contribution of drowsy driving in motor vehicle crashes is difficult to measure. Although reports by police officers who investigate crashes sometimes indicate that a driver was drowsy, data derived from these reports are widely regarded as substantial underestimates of the true scope of the problem.
The current study used data derived from in-depth crash investigations conducted for NHTSA to develop and validate a model to impute driver drowsiness in cases when the driver’s pre-crash alertness or drowsiness could not be ascertained. The model was then used to impute the involvement of drowsiness in all fatal crashes nationwide that involved at least one car, pickup truck, van, minivan or sport utility vehicle.
The study also found that, in percentage terms, the proportion of fatal-crash-involved drivers who were drowsy was greatest among drivers aged 16-20; however, the largest number of drowsy drivers in crashes were aged 21-34. Men were significantly more likely than women to be drowsy, and men accounted for the vast majority of drowsy drivers involved in fatal crashes. Approximately two-thirds of drowsy drivers in fatal crashes had not been drinking alcohol (blood alcohol concentration, BAC = 0.00), however, one-third had non-zero BAC values. Drowsiness was significantly more prevalent among drivers who had been drinking than among those who had not. An estimated 17% of drivers with a BAC of 0.01-0.07 and 20% of drivers with less than or equal to a BAC of 0.08 were drowsy, compared with 11% of those who had not been drinking.
The percentage of drivers who were drowsy was highest among those who crashed on rural collectors and local roads; however, the greatest number of fatal drowsy driving crashes occurred on urban arterials, as the largest proportion of all fatal crashes irrespective of drowsiness occurs on these roads. The greatest number of fatal drowsy driving crashes occurred between 11 p.m. and 2:59 a.m.; the percentage of drivers who were drowsy was highest among those who crashed between the hours of 3 a.m. and 6:59 a.m.
To read more on this study, click here.
