License Plate Recognition Systems (LPRs): Function, Performance, and Considerations for Law Enforcement Agencies

• NCJ Number: 238827
• Date Published: June 2012
• Length: 17 pages
• Grant Number(s): 2009-IJ-CX-K019
• Agencies: NIJ-Sponsored
• Publication Type: Guideline

Annotation

This report presents standards and guidelines for law enforcement agencies to use when contemplating the purchase and deployment of license plate recognition systems.

Abstract

This report was developed by the Small, Rural, Tribal and Border Regional Center of the National Law Enforcement and Corrections Technology Center to provide an overview of license plate recognition (LPR) systems. This overview provides information to law enforcement agencies on the technology used in LPR systems, including their functionality and limitations. This report presents detailed information on what a LPR system is and how it works. LPR systems use optical character recognition (OCR) algorithms that enable computer software to read vehicle license plates and usually consist of three basic components: the camera, the software, and a database of previously read license plates. The report discusses the positive and negative aspects on the three types of LPR systems: fixed, mobile, and portable. The report also includes a section on the performance and expectations of LPR systems in the following areas: uses, light conditions, speed, and accuracy. The following section examines certain items that law enforcement agencies should consider when contemplating the purchase of a LPR system including location, communications, and costs.