While efforts to improve child passenger safety have typically focused on making child restraint systems safer and easier to use, one of the greatest potential means of reducing pediatric injuries from motor-vehicle crashes comes from having all children use the recommended restraint for their size and age. We hypothesized that many caregivers restrain their child passengers based on what is required by their state laws, rather than following best practice recommendations. We tested this hypothesis by developing a rating system for child restraint laws relative to how the wording of the state law compares to best practice recommendations for each age of child from 0 to 13 years. The rating system was applied to laws in each state over a 4-year-time period, and merged with a NASS-GES dataset of crashes from the same period involving children in which the type of child restraint system used in the crash was recorded. Among restrained children, children had 1.66 (95% CI: 1.27, 2.17) times higher odds of using the recommended type of restraint system if the state law at the time of the crash included requirements based on best practice recommendations. This research provides evidence to legislators that strengthening their child passenger safety laws would lead to improved levels of restraint use by child occupants.
The method of coding laws to allow analysis combined with crash data was also adapted to evaluate teen driver crash rates. Ten elements of GDL legislation were identified and ranked on a 0-5 scale: learner age, learner duration, supervised driving hours, more challenging driving hours, intermediate age, driver’s education requirements, nighttime limits, nighttime limit duration, passenger limits, and passenger limit duration. When comparing states with 8 or more strong components of GDL laws to those with three or less, crash rate ratios were reduced by .70 (.30 to 1.4 [95% CI]), 0.59 (0.52 to 0.66) and 0.91 (0.76 to 1.09) for 14-15YO, 16-17YO, and 18-20YO, respectively. When incorporated into the UTMOST tool to estimate the effects on crash distributions of new technologies, the effect of having strong GDL laws in all states was estimated to provide a similar level of reduction in teen crash rates as implementing frontal collision warning or adaptive cruise control in all vehicles.