Where does this come from, and can I check it?

Engineers calculate amber light timing using approach speeds and braking distance. The figure is taken from NIST, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Yes. It sits on the Everyday Life shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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Mondo Knows Facts

Traffic yellow light durations depend on road speed limits

Engineers calculate amber light timing using approach speeds and braking distance

The length of time an amber or yellow traffic signal stays illuminated is not chosen at random. Traffic engineers calculate yellow light intervals using vehicle approach speed, braking deceleration rates, and driver reaction time to ensure drivers can stop safely or cross the intersection completely before red.

Traffic Light Color Types and Stages - YELLOW July 4th 2008 — Micov · CC BY 3.0 · licence · source

Where this comes from

NIST

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Tags: traffic, safety, physics

Traffic yellow light durations depend on road speed limits: the short answers

Where does this come from, and can I check it?: Engineers calculate amber light timing using approach speeds and braking distance. The figure is taken from NIST, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a everyday life fact?: Yes. It sits on the Everyday Life shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.