The risk of fatal injury associated with light trucks during two-vehicle crashes: Estimating equations and conditional maximum likelihood analyses of matched-pair cohort data

The purpose of this study was to estimate the extent to which light trucks influence the risk of fatal injury to drivers of passenger cars when light trucks and cars are involved in severe collisions. A matched-pair cohort design was applied to data from the Fatality Analysis Reporting System for years 1995 through 2001. Data were modeled with a Mantel-Haenszel tabular method, estimating equations risk ratio models, conditional maximum likelihood Poisson models, and conditional maximum likelihood logistic models.;Estimated risk ratios, comparing fatality risks for car drivers with those for light truck drivers, increased as the disparity in vehicle size increased.;Also positively associated with driver death risk were higher age, alcohol use, female sex, absence of seat belt use, air bag non-deployment, and impact to the left or right side of vehicle.;Despite the fact that both passenger cars and light trucks generally perform well in crash tests, this study found that car drivers experienced a strikingly higher risk of death when the two vehicle types were involved in traffic collisions in the US. The marked differences in driver fatality risks are likely attributable to a severe incompatibility due to physical and design differences between cars and light trucks. It appears that passenger cars do not protect car occupants as intended because of the marked differences in the physical characteristics of the vehicles. Car safety features, such as crumple zones, may not perform correctly during collisions with light trucks. Efforts should be made to reduce the design incompatibilities that exist between the numerous types of passenger vehicles produced for the US market.