(Richard M Willis) wrote in
m:

The presence of this superfluous combination of signals causes far
too many
people to think that they must stop UNLESS they have a filter, i.e.
that
the solid green applies only to movements that don't have a filter
even
if that filter is currently dark.

As I understand it, you DO have to stop if the filter isn't showing in
one situation: if the filter light is to the immediate left or right of
the main light, rather than underneath it.

I was led to believe that the law regarding filter arrows is thus:

* If the filter arrow is below the main green light, then if the main
light is illuminated but the filter isn't, you may proceed across the
stop line and wait to turn when it is safe to do so. Once the filter
arrow illuminates you can assume it IS safe to do so as the oncoming
traffic will now be on a red.

* If the filter arrow is beside the main green light, then if the main
light is illuminated but the filter isn't, you must not cross the stop
line, even if it is safe to turn. You must wait for the filter to
illuminate before you can even begin to make the turn.

Interestingly enough I can't find anything in the Highway Code to back
up this belief, despite the fact that a few years back a friend failed
his car test and the examiner told him that one of the faults was to
edge forward at a beside-the-main-light filter.

--
Iain | PGP mail preferred: pubkey @ www.deepsea.f9.co.uk/misc/iain.asc
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