ALPR implementation: Lessons learned

A summary of a RAND report on license plate readers for law enforcement


By PoliceOne Staff

The RAND Corporation, one of the oldest and most diversified of think tanks, produced a comprehensive report on license plate readers for law enforcement that outlined several lessons learned from agencies nationwide.

Here is a summary of those lessons and additional learning points for any police department implementing or updating its ALPR system:

The most successful LPR deployment has the freshest data. (AP Photo/Pablo Martinez Monsivais, File)
The most successful LPR deployment has the freshest data. (AP Photo/Pablo Martinez Monsivais, File)

License Plate Readers (LPRs) act as a force multiplier. The systems can scan and match many more license plates than a squad of officers could do together or individually. LPRs enhance the efficiency of investigations and make the business of traffic stops safer.

LPR can help identify vehicles that have outstanding scofflaw fines associated with their registration. This can help agencies make the case that LPR systems can pay for themselves. For example, officials in Boulder, Colorado, used LPR systems to identify over 100 parking scofflaws who owed over $20,000 to the city. In the first 12 hours that New Haven, Connecticut, ran its system, it identified 119 vehicles with multiple parking violations. The cars were immobilized, resulting in fine payments of $40,000.

Regular training on LPR usage helps produce better results. Officers who take a personal interest in understanding the technology and take advantage of advanced system training can serve as a resource and “champion” for other officers.

There are many benefits to deploying LPRs. One agency reported that 90% of their recovered stolen vehicles came from LPR alerts. While other departments saw a modest increase in stolen recoveries, they made more arrests on local traffic and misdemeanor warrants.

Planning is the key to a successful LPR program. Many agencies are now able to self-fund LPR systems in addition to using state and federal grants. Successful planning goes beyond the funds needed to acquire the system. Remember to include costs for data communication, storage and retrieval; warranty programs or repairs; upgrades and system expansion.

Mobile LPR systems cost less than fixed installations. Deploying a fixed LPR has a variety of variables that impact the total cost. In addition to the hardware, these items include infrastructure to place the camera(s) on; running power and data connections; construction permits and road closures; and hardening the installation against vandalism. Another consideration with fixed systems is the personnel cost. Depending on how the system is deployed, someone may need to be responsible for receiving the alarms and passing them off to patrol officers or investigators.

State and local policies may limit the time that agencies can keep LPR data on file. Long-term storage of LPR data makes the system valuable for investigators and analysts who are looking for crime patterns or the movement of suspects. However, many jurisdictions have implemented retention policies to stem concerns from privacy advocates who condemn any system that tracks the movements of citizens at large, claiming that such a system can be used for political purposes or for harassment. Despite these worries, only 6% of agencies surveyed identified misuse of the LPR data as a concern.

Data storage should not be overlooked when deploying an LPR system. LPR records consist of digital images and the metadata associated with each individual read. The volume of traffic an LPR system records combined with the retention policy will dictate how much storage space is needed on local servers. Cloud storage is virtually unlimited, but has reoccurring costs based on capacity; whereas local storage has a one-time procurement cost if properly sized.

Case law on LPR use is mostly silent, so far. If there is any trend, it leans toward favoring active use of LPRs, where violators are pursued immediately once they are identified. Passive uses, where accumulated license plate reads are analyzed to determine movements and crime patterns, are more likely to be the target of legal challenges. Data collected by non-law enforcement third parties that are then provided to police via subpoena or request is expected to survive constitutional scrutiny.

Data sharing improves effectiveness. Law enforcement agencies operate within well-defined geographic boundaries; criminals are not burdened by such constraints. When data is shared regionally among law enforcement and motor vehicle bureau sources, LPR systems catch more violators and operate more efficiently.

LPR systems should allow for user preferences. Law enforcement agencies have access to import several hotlists from NCIC, their state motor vehicle bureaus and their own warrant files into the LPR system. Combining all these lists allows officers and investigators with different missions to access the information they need. However, if the LPR system does not provide the ability to customize what alarms are active on the individual user level, it could become overwhelming to operate if too many alarms are generated for an individual user. Officers and investigators should have discretion in deciding which alarms the system presents for them to pursue.

The most successful LPR deployment has the freshest data. Most agencies use Wi-Fi or cellular data connections to load files onto the LPRs, although some rely on a flash drive. Stale data files can mean making stops on cars that should have been cleared from the system. Understand how often your agency's data is refreshed and implement rules to provide the updates to your LPR system. The first time you upload a hotlist could take several hours. However, each subsequent update should take far less time.  

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