Traffic lights amber - minimum time period?

[CoolHands]

There is a traffic light near me with a long yellow box shortly before it. There is only space for 1 vehicle. I’ve frequently noticed that it seems to switch quickly and trap the second place person in the box. Today I timed it roughly from looking at my dashcam and it appears to be amber for only 3 seconds.

Is there a minimum time it should be amber before it goes red?

[martinbiz]

CoolHands said:

it appears to be amber for only 3 seconds.

You have answered your own question

[giantdefy]

Traffic Signs Manual Chapter 6

6.1.2.  The period during which an amber signal is displayed is fixed at 3 seconds (s) and the
red/amber signal at 2 s, with a tolerance of 0.25 s either way. This is prescribed in S14‑1‑4. No
variations to these values are permitted. There are no other fixed time periods within the signal
sequence.

[CoolHands]

Ah thanks. Odd, it feels quicker than most.