This report presents results from a randomized experiment conducted by the Mesa Police Department (Arizona) to counter auto theft, using license-plate-recognition (LPR) technology.
The use of LPR technology resulted in 8 to 10 times more plates checked, nearly 3 times as many "hits" for stolen vehicles, and twice as many vehicle recoveries than manual license plate checks and normal patrol. All "hits" for stolen plates, all arrests for stolen vehicles or plates, and all recoveries of occupied vehicles were attributable to the use of the LPR technology. The experiment was conducted in two phases. Phase 1, which lasted 30 weeks, involved LPR operations that targeted high-risk roads, based on analyses of auto theft and recovery locations and the input of detectives. An additional 27 routes were randomly assigned to serve as a control group for the analyses of trends in auto theft. These routes received normal patrol operations without the use of LPR. In phase 2, which was conducted for 18 weeks, operations shifted to larger "hot zones" of auto theft activity. The zones averaged approximately 1 square mile in size. Fifty-four hot zones were identified and randomly assigned to the same conditions as in Phase 1. At randomly selected times during Phase 2, officers worked 18 zones using the LPRs and another 18 zones using manual license checks. The remaining 18 zones served as a control group that received only normal patrol. The study did not find any evidence of crime displacement or a diffusion of crime control benefits associated with either form of patrol in either phase. The report also discusses study limitations, issues for future research, and policy implications of the results. The LPR technology is explained in detail. 9 tables and 105 references
Report (Grant Sponsored)
Date Published: December 1, 2011