S.W.A.T. Organization

The relative infrequency of SWAT call-outs means these expensively-trained and equipped officers cannot be left to sit around, waiting for an emergency. In many departments the officers are normally deployed to regular duties, but are available for SWAT calls via pagers, mobile phones or radio transceivers. Even in the larger police agencies, such as the Los Angeles PD, SWAT personnel would normally be seen in crime suppression roles—specialized and more dangerous than regular patrol, perhaps, but the officers wouldn’t be carrying their distinctive armor and weapons.

By illustration, the LAPD’s website shows that in 2003, their SWAT units were activated 255 times, for 133 SWAT calls and 122 times to serve high-risk warrants.

The New York Police Department’s Emergency Service Unit is one of the few civilian police special-response units that operate autonomously 24 hours a day. However, this unit also provides a wide range of services, including search and rescue functions, and vehicle extraction, normally handled by fire departments or other agencies.

The need to summon widely-dispersed personnel, then equip and brief them, makes for a long lag between the initial emergency and actual SWAT deployment on the ground. The problems of delayed police response at the 1999 Columbine High School shooting has led to changes in police response, mainly rapid deployment of line officers to deal with an active shooter, rather than setting up a perimeter and waiting for SWAT to arrive.

Source: Wikipedia