A Sports Utility Vehicle (SUV) is a relatively large and heavy car, with higher ground clearance than regular cars. As early as 2005, Van Kampen et al. [8] described a steady increase in mass differences between cars, particularly between the compact class and the SUV class. When two vehicles of different masses collide, the lighter vehicle takes a bigger hit than the heavier vehicle. This principle is illustrated by crash studies, that show that the fatality risk for occupants of regular cars is significantly higher when crashing with an SUV, whereas the fatality risk for SUV occupants is significantly lower [37] [38]. SUVs are therefore safe for their occupants, but present an increased risk to other traffic. However, the American crash study by Monfort and Nolan [38] notes that in fatal crashes between regular cars and SUVs, mass differences decreased between 1989 and 2016. We do not know to what extent this decrease also applies to Europe where, on average, regular cars are lighter than in America [39].
The position of SUV bumpers is usually higher than it is for regular cars, which implies that in a collision between these vehicle types, the impact energy is not absorbed to an optimum degree and the smaller car risks sliding under the SUV [40]. In America, the car industry introduced a standard to lower the energy-absorbing structure behind the SUV bumper to the same height as is common for regular cars. There is no consensus about the safety effect of this voluntary measure. Studying American crashes between SUVs and regular cars, Baker et al. [41] found that the fatality risk for drivers of regular cars decreased when the height of the energy-absorbing structure of the two vehicle types no longer differed. Again on the basis of crashes, Ossiander et al. [42], however, found no effect of lower SUV bumpers. Contrary to the study by Baker et al. [41], they not only corrected for the effects of seat belt usage and vehicle mass, but also for other factors, such as road type, speed limit, and driver characteristics.
No crash studies are known comparing the (un)safety of SUVs to regular cars for vulnerable road users such as pedestrians and cyclists.
