In the U.S., the use of emergency lighting on vehicles varies from state to state, and sometimes, even district to district. It’s safe to say that in most areas, emergency lights are limited to first responders and emergency vehicles, with some exceptions.
There are several types of emergency lights used today with the two most common being roof-mounted single beacons and light bars.
Roof-Mounted Single Beacons
First used in 1948, beacons are the original emergency light, the ones you see depicted in older movies and TV programs. They feature either rotating lights or strobes. The use of beacons is declining, though some agencies still use them out of traditional or lack of funds to replace them. Until recently, the Michigan State Police used beacons on all of its patrol cars, but is now replacing them with more modern lighting.
Most beacons are permanently mounted on the roof. Portable beacons are also available with a magnetic mount that allows the user to affix it to the roof when needed. These are used primarily by people such as volunteer firefighters, detectives in unmarked cars, and freight yard managers. The portable beacons are used more frequently today given their versatility.
Light bars have replaced the beacon as the emergency vehicle light of choice today. The first light bars were a metal bar attached to the roof of the vehicle with two rotating beacons attached on either end of bar. Other components such as sirens could also be added to the bar.
Today’s light bars are elongated domes that integrate various components such as sirens, mirrors, and different types of lights into a single unit. Light bars can be configured in various ways, and can include fixed, rotating, strobe, or LED lights and offer programmable flash patterns.
Other types of lighting, such as integrated vehicle lights, body mounted lights, and interior mounted lights are also being added to emergency vehicles.