An evaluation of the specific deterrent effects of vehicle impoundment on suspended, revoked, and unlicensed drivers in California.

There have been a number of studies conducted during the past two decades that convincingly demonstrate that license suspension and revocation are some of the most effective countermeasures currently available for attenuating the traffic safety risk of problem drivers. At the same time, it is also known that most suspended/revoked (S/R) drivers violate their illegal driving status and continue to drive, accruing traffic convictions and becoming involved in crashes. In an attempt to strengthen license actions and to better control S/R and unlicensed drivers, California enacted two laws effective January 1995 which provide for the impoundment and forfeiture of vehicles driven by S/R and unlicensed drivers. The study described in this paper evaluates the impact of vehicle impoundment on the 1-year subsequent driving behavior of S/R and unlicensed drivers who experience this sanction. The results show that drivers with no prior convictions for driving while S/R or unlicensed whose vehicles were impounded have, relative to similar drivers whose vehicles were not impounded: 23.8% fewer driving while suspended/revoked or unlicensed convictions; 18.1% fewer traffic convictions; and 24.7% fewer crashes. The differences between the impound and no-impound groups are even larger when the driving records of repeat offenders (i.e. drivers with prior driving-while-S/R or unlicensed convictions) are examined. Repeat offenders whose vehicles are impounded have 34.2% fewer driving-while-S/R or unlicensed convictions, 22.3% fewer traffic convictions and 37.6% fewer crashes. These findings provide strong support for impounding vehicles driven by S/R and unlicensed drivers.