Richard J.:
That was probably a junction where there is a separate complete traffic
signal controlling turning traffic. In other words, you have something
like this:

Red Red
Amber Amber
Green Green-arrow

Just by the way, the analogous layout in *some* jurisdictions in
North America would use arrows for all three lights on the left-turn
signal.
--
Mark Brader, Toronto | There is no step function between "safe" and "unsafe".
| -- Jeff Janes