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

• Published date: 01 March 2012
• Author: Bruce Taylor,Daniel Woods,Christopher Koper
• Date: 01 March 2012
• DOI: 10.1177/0734016811425858
• Subject Matter: Articles

Combating Vehicle Theft

in Arizona: A Randomized

Experiment With License

Plate Recognition

Technology

Bruce Taylor

1

, Christopher Koper

2

, and Daniel Woods

3

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.

Keywords

law enforcement/security, crime prevention, evaluation research

1

NORC at the University of Chicago, Bethesda, MD, USA

2

George Mason University, Fairfax, VA, USA

3

Police Executive Research Forum, Washington, DC, USA

Corresponding Author:

Bruce Taylor, NORC at the University of Chicago, 4350 East West Highway, Bethesda, MD 20814, USA

Email: taylor-bruce@norc.org

Criminal Justice Review

37(1) 24-50

ª2012 Georgia State University

Reprints and permission:

sagepub.com/journalsPermissions.nav

DOI: 10.1177/0734016811425858

http://cjr.sagepub.com

The field of vehicle theft research has been growing and receiving increasing attention by

the research community in recent years (Clarke & Harris, 1992; Herzog, 2002; Kriven &

Ziersch, 2007; Levy, 2008; Maxfield, 2004; Rice & Smith, 2002; Walsh, 2009; Walsh & Tay-

lor, 2007a, 2007b). This is good news as this is an all too common offense (despite the recent

downward trend) with around a million vehicle thefts occurring per year (ranging from 1.64

million in 1990 to just fewer than 800,000 in 2009; Federal Bureau of Investigation [FBI],

2010). Also, research suggests that 90%of vehicle thefts are reported to the police, a rate much

higher than for other types of thefts (Krimmel & Mele, 1998). The high frequency and high reporting

rate of vehicle thefts leads to this being a sizeable portion of police work in many jurisdictions.

According to the FBI’s Uniform Crime Reports (UCR), property loss as a result of motor vehicle

theft totaled $7.6 billion for 2005 (down to about $6.4 billion for 2008; FBI, 2009a, 2009b), account-

ing for 11%of Part I offenses recorded by the FBI (Lamm Weisel, Smith, Garson, Pavlichev, &

Warttell, 2006). The volume of vehicle theft rose from the mid-1980s to the early 1990s and then

began to decline (Newman, 2004). While the data indicate a downward trend in vehicle theft

since the 1990s, this may be due to the results of a number of enhancements to vehicle security

at the manufacturer level (Newman, 2004). However, motor vehicle theft remains a significant

problem for the police across the United States. Although about 57%of the value of vehicles

stolen is recovered, most thefts do not result in an arrest (FBI, 2009a, 2009b). The arrest rate

for vehicle theft nationwide was only about 10%in 2009 (FBI, 2010).

One recent innovation that could serve as a useful tool for law enforcement in addressing auto

theft is license plate recognition (LPR) technology. Like many new technologies, there is evi-

dence that an increasing number of law enforcement agencies (LEAs) are turning to LPR equip-

ment as a tool to address vehicle theft. However, this equipment is expensive and to date there is

little rigorous evidence of its effectiveness. While there may be some obvious efficiency gains

from automating the process of checking license plates, it is unclear if this equipment is effective

at driving down the number of vehicle thefts or increasing the arrest rate for vehicle theft. These

are the key questions examined in this article based on data collected during a randomized

experiment with LPR equipment in Mesa, Arizona.

Literature Review

LPR is a relatively new technology in the United States but has been used since the 1980s in

Europe to prevent crimes from vehicle theft to terrorism (Gordon, 2006). LPR is based on optical

character-recognition technology. LPRs serve as a mass surveillance system for reading license

plates on vehicles using a system of algorithms, optical character recognition, cameras, and data-

bases. Through high-speed camera systems mounted to police cars, LPR systems scan license

plates in real time, and compare them against databases of stolen vehicles, as well as vehicles

connected to fugitives or other persons of interest, and alert police personnel to any matches.

Under ‘‘Description of Intervention,’’ we provide a detailed description of LPR technology. The

use of LPR technology is part of a broader movement in law enforcement to adopt new technol-

ogies such as surveillance systems (see Koper, Taylor, & Kubu, 2009). An extensive literature

has emerged on the use of surveillance systems, particularly closed-circuit television (CCTV; see

Welsh & Farrington, 2008). Based largely on studies in the United Kingdom, this technology

appears to be effective in reducing vehicle crimes on public streets and in parking facilities. How-

ever, there has been little research to date on LPR surveillance technology.

The United Kingdom has the greatest amount of law enforcement related experience with LPR

technology, which it used to aid in responding to attacks by the IRA in the 1990s (Manson,

2006). In fact, the Home Office made £32.5 million available to British police for the years

2005–2007 for the use of LPR (see http://police.homeoffice.gov.uk). One of the first U.K. agencies

Taylor et al. 25