This study used a quasi-induced exposure (QIE) analysis technique to estimate annual fatal crash involvement rates for S/R, unlicensed, and validly licensed drivers in California from 1987 through 2009 using fatal crash data obtained from National Highway Traffic Safety Administration’s Fatality Analysis Reporting System (FARS) and California Department of Highway Patrol’s Statewide Integrated Traffic Records System (SWITRS). The annual fatal crash involvement ratios range from 0.81 to 0.91 for validly licensed drivers, 1.44 to 4.29 for S/R drivers, and 1.60 to 3.50 for unlicensed drivers, respectively, over the 23-year time period studied. The annual at-fault overinvolvement rates for S/R and unlicensed drivers relative to validly licensed drivers range from 1.57 to 4.93 for the S/R group and from 1.84 to 4.10 for the unlicensed group. Although the annual rates fluctuate, S/R and unlicensed drivers were overinvolved as at-fault drivers in fatal crashes every year relative to validly licensed drivers. The fatal crash involvement ratios obtained for all years combined (1987 through 2009) are 0.86 for validly licensed drivers, 2.23 for S/R drivers, and 2.34 for unlicensed drivers. The at-fault overinvolvement rates for the S/R and unlicensed groups, relative to the validly licensed group, are 2.60 and 2.73, respectively, for this 23-year period. The study results provide strong evidence that S/R and unlicensed drivers are much more hazardous on the road than are validly licensed drivers. Compared to licensed drivers, those who drive without a valid license are nearly three times more likely to cause a fatal crash relative to their exposure. The study findings strongly justify the use of countermeasures, including vehicle impoundment, to control S/R and unlicensed drivers and to reduce crashes caused by these drivers. (Author/publisher)
Abstract