The average police-reported speed in fatal crashes for the unbelted population has increased from about 50 mph in the early 1980's to almost 55 mph in 1996, while it has remained between 46 and 47 mph for the belted population. This provides further evidence that unbelted individuals are involved in more severe crashes. This estimate of the relative odds of ejection is adjusted for such factors as safety belt use and the occurrence of rollover, which leads to the conjecture that it is due to an intrinsic difference in the dynamics of being involved in a crash in a light truck compared to a crash in passenger car. Since the fraction of light trucks involved in fatal crashes has increased from about 21 percent in the early 1980's to about 31 percent in 1996, this factor also contributes to explaining the increased prevalence of ejection. Finally, the driver's age was found to be an important predictor of the probability of ejection.
Younger drivers are more likely to be involved in ejection crashes.
The average age of unbelted individuals in fatal crashes is about 35 compared with the average age of about 45 for the belted individuals. The average driver age in rollover crashes is about 33, while the average driver age in ejection crashes is about 32. In spite of the general increase in the average age of fatally injured individuals, the average driver age in rollover and ejection crashes has grown very little from 1982 to 1996. This analysis leads to the conclusion that the increase in the prevalence of ejection among the unbelted individuals in fatal crashes during the 1980's and 1990's can be explained by the increased severity of crashes in that population, as evidenced by the increase in the rollover rate and speed, together with the increase in the presence of light trucks in those crashes and the young age of drivers involved. The unbelted population consists of individuals who remained unbelted in spite of the enactment of safety belt use laws and public information and education campaigns.