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Back to Archives | Back to June 2008 Contents 

Applying Digital In-Car Video Systems to Manage Evidence and Obtain Prosecutions

By Joni Eddy, Assistant Chief of Police, Lewisville, Texas; and Joe Martin, Director of Business

In-car camera technology is one of the best tools agencies have to protect themselves and their officers. This article describes one agency's experiences in selecting and deploying digital video systems in its patrol fleet.

ince the 1980s, in-car video cameras have been used in police vehicles to improve officer safety, enhance agency accountability, and assist in securing prosecutions. Boosted by more than $21 million in grants from the U.S. Department of Justice’s Office of Community Oriented Policing Services (COPS) between 1994 and 2004, the number of in-car cameras deployed by state police and highway patrols has increased significantly over the past fifteen years.

With video cameras becoming a standard feature in law enforcement vehicles across the United States, breakthroughs in digital technology have resulted in important advancements in the ability to record, store, and even search video evidence. The entire video product market, from professional broadcast camcorders to consumer point-and-shoot cameras, has made the transition from analog to digital, and the trend has extended to in-car video systems.

The benefits of switching to digital in-car video systems are evident in the recent experience of the Lewisville, Texas, Police Department. Lewisville, a city of 94,000 people located 15 miles north of Dallas, used analog video cameras in their vehicles for years. But the video evidence obtained from these cameras came at the expense of demands on manpower and time for the department’s 139 officers.

The analog video cassettes used in Lewisville police cars produced quality images but were prone to damage or degradation after a few uses. In addition, locating specific videotaped incidents for a court appearance or internal review was a time-consuming process. To ensure proper access, an officer would file a formal request to have a clerk locate the video in the agency’s overflowing storage room. Once obtained, the officer would have to use a VCR to search through the numerous traffic stops included on the tape to locate the relevant incident—a process that was both time-consuming for the officer and potentially harmful to the videotape.

Switching to a Digital Solution

Recognizing the need for a more efficient alternative to their analog system, Lewisville chief of police Russell Kerbow sought a new solution that would streamline the process and protect the chain of evidence from the car to the courtroom.

After an extensive review of available products, the department selected a solid-state digital video recording system from Panasonic. The system records digital video stored on removable high-capacity cards that can store dozens of hours of video depending on the resolution selected. The system can be operated through touchscreen controls on the vehicle-mounted laptops (see figure 1).

Figure 1. Officer Paul Nathan of the Lewisville Police Department using his vehicle's digital video system.
Photo courtesy of the Lewisville Police Department

One advantage digital recording brings to law enforcement is “pre-event recording.” Lewisville’s previous in-car system only started recording when a triggering event occurred, such as the officer turning on the emergency lights. By the time the recorder started, however, the activity that led to a traffic stop was often missed. By contrast, the digital video system works like a television digital video recorder (DVR): it is always recording to an internal buffer and saves the buffered video when a triggering event occurs. Up to two minutes of video footage from before the emergency equipment is activated is captured. This pre-event information can be critical for prosecutors, judges, and juries to get the full context of an officer’s actions.

“This means that we can often catch the actual offense, and not just the activities that transpire after it occurs. This is simply better evidence,” said Chris Lee, technology operations manager for the City of Lewisville.

Protecting the Chain of Evidence

Another advantage of the digital video system is the higher level of integrity in managing the chain of evidence. The entire process is automated and protected by auditable systems. Any video stored on the storage card is automatically uploaded to the department’s central servers using Wi-Fi hotspots placed at the police station and in strategic locations throughout the city.

“We do not have to worry about having officers handle videotapes to transfer them to a storage facility,” explained Lee. “In a digital environment, the cars pull up to the police department, and the [storage] cards are in a vault that the police officers do not have access to. The officers do not have a role in the process.”

Once the video is stored in the department’s servers, it is easy for the property and evidence departments to archive, search, manage, and track the evidence. Using a management system developed by the equipment manufacturer, the system automatically establishes metadata tags that make each video easy to locate. The system includes permissions settings and an access record to ensure that videos are properly accessed and utilized. The stored video can be searched by categories such as incident, car number, officer name, or date and time of day.

Because captured events have varying levels of importance, Lewisville is also able to apply its own standards to how long each is stored. For example, all hit-and-run footage can be stored automatically for two years, while speeding infractions are kept for six months, accommodating local retention policies and statutes of limitations.

Coordinating with the Court System

In the end, recording and storing video evidence is just the prelude to what really counts: using video footage to obtain a successful prosecution. To make the best use of this evidence, the Lewisville Police Department has integrated its video system with the city’s court system.

By connecting the networks of the department and the courtroom, prosecutors and court administrators are able to locate video footage instantly and display it during traffic hearings. If an officer has video evidence of a DWI that needs to be presented in court, the patrol officer just has to bookmark the video with a report number. The information is sent to the property and evidence department, and the appropriate staff can then transfer the designated segment of data to the courts.

“There have always been people who choose to question the validity of a traffic stop by taking their chances in court,” said Lee. “We have a projector set up in the courtroom that allows officials to rapidly access the evidence associated with a case and review it with all those involved including the defendants. When the suspects see the evidence, it often results in an immediate plea, which removes significant workload from the court system.”

Looking Ahead

For the Lewisville Police Department, digital in-car video systems have resulted in significant savings in time and resources, as well as stronger cooperation with prosecutors and district attorneys. As digital video and wireless communications technologies evolve, in-car video will continue to provide new ways to help law enforcement officers manage evidence and keep the peace. ?

Mobile Video Considerations for Law Enforcement Agencies

On April 30, 2007, the U.S. Supreme Court issued a landmark ruling that affirmed what police officers around the country already knew: in-car cameras are one of the most important tools to protect officers and their agencies. In Scott v. Harris, which involved the termination of a high-speed chase that resulted in serious permanent injury to the fleeing driver (Harris), the Court found “the car chase respondent initiated posed a substantial and immediate risk of serious physical injury to others, [Deputy] Scott’s attempt to terminate the chase by forcing respondent off the road was reasonable, and Scott is entitled to summary judgment.”

Video recorded during the pursuit provided the justices with critical information that led to the 8–1 decision favoring Deputy Scott: “Viewing the facts in the light depicted by the videotape, it is clear that Deputy Scott did not violate the Fourth Amendment.” In his written opinion for the majority, Justice Antonin Scalia stated, “[Harris]’s version of events is so utterly discredited by the record that no reasonable jury could have believed him. The Court of Appeals should not have relied on such visible fiction; it should have viewed the facts in the light depicted by the videotape.”1

Since its introduction over three decades ago, mobile video technology has had a significant impact on the law enforcement profession, and more agencies are installing video systems every year. In the past, most mobile video systems recorded to video cassettes; however, the technology has evolved, and now almost every manufacturer of mobile video equipment has abandoned analog, tape-based recorders in favor of digital recording systems. Although the fundamental functions of the devices remain the same, agencies must be aware of some significant differences between analog and digital video systems.

Analog recording systems capture the images and sounds on a tape that is typically removed from the vehicle and simply stored on a shelf. Digital systems, on the other hand, offer a wide variety of options for recording video and transferring the images and sounds—recorded as data files—to a storage system. Some systems record directly to DVDs or other removable devices that can be stored on a shelf. Others record to an electronic device, such as a hard drive or a compact flash card, that can be removed and plugged into a computer to download media files to a central server. Another popular option is wireless download, which automatically transfers files from a vehicle to a storage system while the vehicle is being refueled or parked at patrol headquarters. In nearly every case, however, an agency must have adequate storage capabilities to handle the very large storage demands of audio and video files. Some agencies have found that storing digital video assets can require several times the server space of all other department records combined! It is very important for agencies to work with their equipment manufacturer and their information technology departments to determine their storage needs. Agencies should also consult their legal adviser or state attorney to determine the retention requirements for their jurisdictions.

One other very important consideration is the integrity of digital video files. Most digital recording systems give operators several recording options, often enumerated in terms of storage capacity. Increasing the compression of video files may allow the user to store more hours of video footage in the patrol vehicle, but high compression could result in a severe loss of video quality. The IACP recommends that agencies record only on the highest-quality setting.

The IACP is working with equipment manufacturers to establish minimum performance specifications for digital video systems, which should be completed by late 2008. More information can be found on the IACP Web site (at the Research Center’s Cutting Edge of Technology project page) or by contacting Al Arena via e-mail at


1Scott v. Harris, 127 S. Ct. 1769 (2007). The full text of the opinion, including a link to the video from the case, can be found on the Supreme Court Web site at . This case marks the first time the Court has posted video evidence on its Web site.



From The Police Chief, vol. LXXV, no. 6, June 2008. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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