“…We selected the independent variables for this study according to Haddon's matrix 21 and subsequent research, 5,7,8,[22][23][24] which have identified the salient driver, vehicle, and environmental factors that increase crash and injury risk. These studies have demonstrated repeatedly that driver age and sex, speeding, alcohol and safety belt use, time of day, day of week, vehicle type, weather and roadway conditions, and (for teenage drivers) number of passengers are all associated with the risk of fatal crash involvement.…”