Working Paper: Automated License Plate Readers, Vehicle Theft, and Clearance

Do fixed automated license plate reader (ALPR) networks reduce motor vehicle theft or improve case outcomes? We use the staggered deployment of fixed ALPRs supplied by Flock Safety across 216 U.S. law enforcement agencies and National Incident-Based Reporting System data from 2017 through 2023. A Sun-Abraham interaction-weighted event study accounts for heterogeneous effects under staggered adoption. Motor vehicle theft fell 11.0 percent after deployment (95 percent CI [-17.3, -4.2]). MVT relative to the same agencies’ other property crime fell 5.2 percent ([-9.3, -0.9]), while the change in other property crime was not distinguishable from zero (−6.1 percent [−12.2, +0.4]). MVT arrest clearance rose 15.9 percent ([+7.3, +25.0]), although the increase began during the final three pre-deployment months, weakening causal attribution to the cameras. Among recorded recoveries, the conditional median recovery lag fell by about 0.28 days; measures covering all stolen vehicles show no aggregate improvement. Fixed ALPR deployment is associated with lower theft and higher clearance, alongside a modest reduction in recovery lag among recorded recoveries that does not extend to all stolen vehicles.