BLACKED OUT

Also refers to rolling up to a call-in progress with all of your vehicle lights turned off. Many agencies use "black-out switches" that will deactivate your brake lights. You can turn off all of your lights as you approach, and also kill your brake lights, so the light doesn't announce your arrival. Some officers cruise alleys "blacked out" looking for taggers, burglars, hookers, etc. Sometimes referred to as stealth mode.

When all units are on calls for service and calls are holding, and there are no units who can clear for priority calls, the shift is "blacked out".