Reactive patrol is police responding to specific requests from individuals or groups in a community that provides “immediate” response to calls. Reactive patrol provides help to ensure that calls are responded to in an efficient and timely manner. Reactive patrol also involves the follow-up investigations required to get additional information to prosecute or otherwise help with assistance of the community. Reactive patrol is different from proactive control in the sense that reactive patrol is employed when a crime is or has already been committed and/or reported.
Proactive policing is based on the concept of preventing crime, and making an appearance in the community to ensure they know there is assistance there for their own protection and safety.
Proactive policing also provides a sort of deterrent for potential crimes and criminals due to the fact they know there is law enforcement active and interested in what is going on in the community. If police agencies only adopted one or the other, proactive, or reactive policing, the law enforcement system would become unbalanced.
If proactive policing is the only type being employed, preventative measures might go so far that they begin to infringe on individual rights. If only reactive policing were used, there would be a rise in crime, because people would know there would only be a chance of them getting caught after the act had already been committed.