Cletus R. Mercier

AGE AND GENDER AS PREDICTORS OF INJURY SEVERITY IN HEAD-ON HIGHWAY VEHICULAR COLLISIONS

Whether age or gender or both influenced severity of injuries suffered in head-on automobile collisions on rural highways was assessed. The initial hypothesis was that, because of physiological changes, and possibly other changes related to aging (including loss of bone density), older drivers and passengers would suffer more severe injuries when involved in head-on collisions. Results of logistic regression analysis indicate that four separate factors, incorporating 14 individual and interactive variables, were strongly related to injury severity. Individual variables included age of driver or passenger (either linear or quadratic), position in the vehicle, and form of protection used, along with a set of interactive variables (such as age and position). The importance of age-related effects in injury severity is verified by hierarchical and principal components logistic regression models, amplifying findings of exploratory stepwise logistic analysis. Variations in findings resulted when the population was divided by gender. Although age remained a very important factor in predicting injury severity for both men and women, use of lap and shoulder restraints appeared to be more beneficial for men than for women, while deployed air bags seemed more beneficial for women than for men.

Age and Gender as Predictors of Injury Severity in Broadside and Angle Vehicular Collisions

Is age a factor in injury severity in the occurrence of broadside and angle collisions of automobiles on rural highways? The primary hypothesis is that older drivers and passengers would suffer more severe injuries than younger adults when involved in these types of collisions. Injury severity was chosen as the dependent variable, with nine independent or interaction variables tested. Independent variables were selected if they improved the model significantly, at a significance level of p < .05. Relationships were verified using Hierarchical Regression Analysis and Principal Components Regression. Findings varied, depending on the point-of-impact examined and the vehicle occupant gender. Age (linear and quadratic) proved to be a significant predictor of injury severity for all, but it was slightly greater for females than for males. Use of lap and shoulder restraints proved to reduce injury severity, but results are less certain for women. Air bags deployed were significant predictors when the vehicle was struck in the rear third, but only for females. One of the study’s surprises was the lack of strength of the variable of occupant position relative to the point-of-impact, except as part of interaction variables with age—both linear and quadratic. Position refers to the location of the occupant relative to the point-of-impact, with the position furthest from impact presumed as being the safest.

PERSONALITY STRUCTURE OF ELDERLY DRIVERS

This paper reports the factor structure of a 37-item personality questionnaire intended to be predictive of driving performance in elderly persons. Subjects were 191 persons 63 years of age or older, about half of whom also were given perceptual/cognitive tasks and drove on a closed driving course. Although the personality questionnaire did not predict driving skill, the factor structure of the questionnaire is of interest. Of several factor analyses, the most satisfactory was a 2-factor solution. We interpreted the approximately orthogonal factors as measuring what we labeled Competence and Emotionality.