Police cars or ambulances have lights on their roof, which are on when the sirens are on. What are these lights called? Is it something like signal lights or alarm lights?

I am looking for an official term/word.

Example sentence:

……………… create an interesting atmosphere at night.

  • Are you looking for the term specific to a mounted lightbar, or any form of similar warning lights. For example, unmarked police cars may have them hidden somewhere, like behind the grill, and when a private vehicle is used, they may stick a portable warning light on the dashboard or on the roof with a magnet. Those wouldn't be called a lightbar, they would be referred to by a more generic term. – fixer1234 Jul 2 '17 at 8:18
  • @fixer1234 I agree that there would be a more generic term. However, OP specified lights on the roof, which I believe refers only to the lightbar. – as4s4hetic Jul 2 '17 at 8:54
  • @fixer1234: yes, any form of warning lights, also the portable ones you mentioned. – user192211 Jul 2 '17 at 10:47
  • When I was a kid police cars were referred to as "cherry tops". Of course, this was when they had a single red rotating beacon on top. – Hot Licks Jul 2 '17 at 11:51

The official term is lightbar/light bar

(noun) A bar mounted on the roof of a vehicle, such as a police car, with rotating beacons or other lights to provide a visual warning.

It is also labeled as such on the Merriam-Webster Visual Dictionary Online. enter image description here

(Source: http://www.visualdictionaryonline.com/society/safety/crime-prevention/police-car.php)

A generic term for these lights seems to just be "Emergency vehicle lights." I have looked for a more specialised word, but even websites that sell these lights refer to them as such.

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  • Thanks for your answer! Do you also have an idea for a more generic term, which would include portable lights like described by fixer1234? I think some of those portable forms also can be applied on the roof. – user192211 Jul 2 '17 at 10:50

I guess you are looking for the word "beacon lights".

An excerpt from Wikipedia

Vehicular beacons are rotating or flashing lights affixed to the top of a vehicle to attract the attention of surrounding vehicles and pedestrians. Emergency vehicles such as fire engines, ambulances, police cars, tow trucks, construction vehicles, and snow-removal vehicles carry beacon lights

Here is a picture of such a light (Source: http://www.thehindubusinessline.com)

Beacon light in a police car

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  • 1
    Beacon is the right word, @Harmless Psycho: 'light bar' refers to a more specific form-factor and you can note that the definition of 'light bar' in that answer contains the word 'beacon.' – English Student Jul 20 '17 at 11:20
  • Beacon is still used in UK legislation, even though almost all UK emergency vehicles use LED or strobe lights. But it's not a term in common use. – Andrew Leach Aug 2 '19 at 17:06

Blues and twos create an interesting atmosphere at night.

Although British, and arguably informal, blues and twos refers to the lights and sirens together.

blues and twos NOUN

British informal
1 The flashing lights and siren used on a police car or other emergency vehicle when responding to an incident. Also later "on (also under) blues and twos".
2 The emergency services (frequently the police).

1980s; earliest use found in Autocar. From the plural of blue + the plural of two, with reference to the blue flashing lights and (typically) two-tone siren used on an emergency vehicle.

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