# INTERACTIONS OF OCCUPANT AGE, VEHICLE WEIGHT, AND THE PROBABILITY OF A DYNING IN A TWO-VEHICLE CRASH 31A1 ELYN

Previous studies have considered the likelihood of injury and fatality to car occupants as a function of their own vehicle's weight and of the other vehicle's weight (for two-vehicle collisions). Since occupant age has an effect on the likelihood of injury or fatality, and since it varies strongly with car size, this study is intended to determine these relationships in a set of mass accident data while controlling for occupant age. The data set chosen for analysis is large enough that we are able to use the probability of a fatality (given a crash) as a dependent variable. Two Specific models are developed here. The first assumes that occupant age is independent of the effect of the weight of each vehicle (in a two-vehicle crash) and of the interaction between the two weights. The probability of fatality (given a crash) is calculated as a function of age for the entire population. The second model assumes that occupant age can be interrelated with one's own vehicle weight, but that the effect of the other vehicle's weight is independent of the first two factors. In this model, the probability of fatality (given a crash) is computed for each category of one's own car weight. From the first model we conclude that the probability of fatality is quadratic with age-i.e., that the probability of fatality increases faster as one gets older. From the second model we conclude that the probability of fatality as a function of age increases more rapidly for the occupant of a small car than for the occupant of a large car. Of the three kinds of two-car interactions -small-small, small-large, and large-large - the first model indicates that the occupants of a small car in a collision with a large car have the -highest fatality probability, the occupants of a large car striking a small one have the lowest, and the other two (small-small and large-large) exhibit nearly equal fatality probabilities. The second model indicates that the small-small and large-large effects are a function of occupant age such that younger persons are somewhat better off (i.e. have a lower probability of fatality) in a small-small collision than in a large-large and older perons are worse off.

• Corporate Authors:

Highway Safety Research Institute

Ann Arbor, MI  United States  48109
• Authors:
• Preston, F L
• Publication Date: 1975-8

## Media Info

• Features: Figures; Tables;
• Pagination: p. 1-8
• Serial:
• HIT Lab Reports
• Volume: 5
• Issue Number: 12
• Publisher: University of Michigan Transportation Research Institute

## Filing Info

• Accession Number: 00132168
• Record Type: Publication
• Source Agency: Highway Safety Research Institute
• Files: TRIS
• Created Date: Nov 23 1977 12:00AM