The majority of police patrol cars in the United States are equipped with security cameras to record criminal activity and to identify criminals. Security cameras also protect police officers and their suspects, to serve as evidence that proper arrest procedures are followed.

Some patrol cars have cameras powerful enough to identify license plates to quickly determine whether a car is stolen or belongs to a wanted criminal. Cameras like these utilize inferred technology. They may sit on top of patrol cars while a computer wired through the trunk runs tag numbers on cars. If a tag comes up stolen or registered to a criminal, an alert comes up on the officer's laptop. If there are more than one of these cameras mounted on top of a patrol car, they can read car plates passing from either direction at the same time.

Security cameras are fast becoming an important tool in crime prevention. Several government departments, local municipalities and businesses have been using them for years to deter criminals or catch them in the act of committing crimes. Footage captured on these cameras has been responsible for identifying bank and ATM robbers, store break-ins, rapes, murders, and other crimes.

More and more cities throughout the United States and other countries have installed closed-circuit television cameras (CCTV). These devices allow the police to monitor activity, to discourage crime and catch those breaking the law in the act. These cameras are usually out in the open, with signs warning you that your actions are being recorded. The security camera systems transmit the images to monitors at local police stations.

When it comes to using security camera recordings as evidence in criminal trials, the quality of the recording is important. The video should be sharp enough for a judge and jury to recognize the action taking place and the people involved. In some cases, such clear evidence is beneficial in helping to prosecute offenders of the law.