Because of this, it is not regarded as an offence to go through an amber
light. The amber phase is necessary to make red enforceable because only
with it is the road user given sufficient warning that he will be able
to stop before the red light.

Truebrit" wrote:
Going from green to amber I would tend to agree with you but when the
lights are in the opposite sequence and are going from amber to green
there are far to many cowboys who look upon that amber light to get their
clog down.
I much prefer our system here in N America where our lights go from red
to green with no amber in between and that green does not appear until
the red in the cross direction has been lit for five seconds after
showing the warning amber.

"NY" wrote: There are people who set off on amber instead
of waiting for green, although at least the red is also illuminated during
this time to send a "stay stopped" message. I wonder whether the amber
warning of green was partly included originally to say "time to put move
the gear lever from neutral to first (or neutral to drive in the case of
automatic)" so people were not left doing this when the light went green -
which could lead to rear-end shunts if the car behind is already prepared
to set off and doesn't notice/expect that the car in front isn't ready yet.

Turning left/right (delete as applicable) is probably a good one. What do
pedestrian lights show during this time? Green/walk? It needs pedestrians
to be aware that cars will turn, even if they (cars) *should* give way to
them.

The pedestrian has the right of way in such instances and has a green "walk"
sign. As I said the driver can only proceed and make the turn after coming
to a FULL stop and only then when it is safe to do so.
Truebrit.