The goal of project is to better understand the public safety impact of automatic license plate readers (LPRs). Use of LPRs has spread rapidly across law enforcement agencies in the United States. While a national survey of law enforcement agencies (LEAs) estimates that approximately 66% of LEAs with more than 100 officers had LPRs by 2016 (Lum et al., 2016), the rapid adoption has taken place in a relatively low information environment. Few rigorous studies have been conducted to understand the efficacy of ALPRs in achieving relevant public safety outcomes or best practices for privacy and data protection.

Existing research suggests that LPRs can be effective for increasing recovery of stolen vehicles and arrests for auto thefts (Koper et al., 2013, 2019, 2021; Ohio State Highway Patrol, 2005; Ozer, 2010; Taylor et al., 2012), and, under certain conditions, may improve clearance rates for auto theft and robbery (Koper & Lum, 2019).

However, several studies exploring the crime prevention value of LPRs have found varied effectiveness based on several factors. These may include volume and concentration of ALPRs deployed, the type of LPR deployed (e.g., fixed vs. mobile), location of use, the types of databases connected to LPR system and how often they are updated, how officers use ALPRs in the field, and agency pursuit and response policies for officers informed about suspects by LPR technology.

Modern LPR systems can use machine learning to capture a variety of additional information beyond license plate information. This may include information about the vehicle (such as vehicle color and type) that could not be systematically identified previously. This additional information may have implications for both how ALPRs are used for investigative purposes and ultimately their impact on public safety. Considering recent improvements in ALPR technology, the current study seeks to expand understanding of the public safety benefits of LPRs through a multi-site data collection and analysis, focused on fixed-location LPR systems in several large law enforcement agencies across the United States.

This current study will be done through multi-site, quasi-experimental assessment. The study also seeks to expand understanding of privacy protections for collected data, agency policies on collected data, and transparency with the community. How agencies share data and the policies that control that information sharing will be explored by the project team.