Combating Vehicle Theft in Arizona: A Randomized Experiment With License Plate Recognition Technology

Abstract

This article focuses on a relatively new innovation for use by law enforcement, license plate recognition (LPR) systems, in fighting auto theft. While it is a promising technology, there has not been much research on the effectiveness of LPR systems. The authors conducted a randomized experiment to study the effects of LPR devices on auto theft. The authors found that the LPR is achieving its most basic purpose of increasing the number of plates scanned by officers (8 times greater) compared to manual plate checking. Further, when compared to manual checking, the LPR was associated with more “hits” (i.e., positive scans) for auto theft and stolen plates, more arrests for stolen vehicles, and more stolen vehicle recoveries. Unexpectedly, the authors found that manual plate checking by a special auto theft unit (but not LPR scanning by the same unit) was associated with less auto theft 2 weeks after the intervention (based on both police crime reports and calls for police service) than the control group (regular nonspecialized patrol without LPR). Finally, the authors found no evidence of crime displacement occurring from their targeted routes to adjacent areas for any of their models. This study provides evidence that LPR use can achieve demonstrable benefits in combating auto theft (i.e., more plates scanned, “hits,” arrests and recoveries with LPR). These results are impressive for the field of auto theft where so little research tested interventions exist. Future work will involve developing strategies that maintains the documented benefits of LPR use by a specialized unit, but also achieve the benefits associated with manual checking by a specialized unit.