# Truck lights

**URL:** <https://boards.straightdope.com/t/truck-lights/133583>\
**Category:** Factual Questions\
**Created:** [October 23, 2002, 9:09pm UTC](https://boards.straightdope.com/t/truck-lights/133583 "2002-10-23T21:09:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\
**Post date:** [October 23, 2002, 9:09pm UTC](https://boards.straightdope.com/t/truck-lights/133583/1 "2002-10-23T21:09:26Z")

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Why do large trucks and buses have amber lights over the cab?

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**Author:** ![Berkut](https://avatars.discourse-cdn.com/v4/letter/b/a88e57/32.png) [@Berkut](https://boards.straightdope.com/u/Berkut)\
**Post date:** [October 23, 2002, 11:10pm UTC](https://boards.straightdope.com/t/truck-lights/133583/2 "2002-10-23T23:10:17Z")

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They are called Clearance Lights.  
I believe they are used to mark the dimensions of the truck, presumably for obstacle clearance.

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**Author:** ![Anachronism](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Anachronism](https://boards.straightdope.com/u/Anachronism)\
**Post date:** [October 23, 2002, 11:19pm UTC](https://boards.straightdope.com/t/truck-lights/133583/3 "2002-10-23T23:19:19Z")

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The ones on the outside are called clearance lights and are to show the width of the truck. The three in the center are called ID lights and are required on vehicles over 96" (I think) wide.