The signal in this instance means traffic going straight on, may go. Those wanting to turn left (there is always a seperate lane where theres a filter light), must wait until the light turns full green. It is slightly confusing, because this light appears on only 2 of the 4 signals controlling this traffic, but this is the case on most signals with a filter, the filter light is located closest to the filter traffic.
Given that most people here didn't have a clue, I think there should be a mass advertising campaign to raise awareness of this type of signal. This light has been here for 12 years, and still people dont get it.
This one only appears when someone presses the button for the pedestrian crossing to the left turn road. And even then, 9 times out of ten, the peds have got fed up waiting and gone anyway!!! It can be 4 minutes between pressing the button and getting a green man, due to the cycle time of the lights (if you press it too late in one cycle, it wont work and waits for another full cycle, the same happens in the right turn lanes. It waits for a full cycle unless you pull up early in the cycle). This makes it worse because drivers cant see what they are waiting for in the left lane on the above signal.
These are more permutations that exist locally to me. In general the ones with the signal tacked onto the side, are better understood by drivers, as they appear "seperate" from the tri-colour standard lights. (Would most people here understood these variations I have just drawn?) Also the ones with a right or left arrow are also better understood, as these generally relate to the minority of traffic, hence the "filter" light, with the main green relating to the majority. The reverse applies in my original example, contributing to some confusion!
I think it would be far better in the circumstance I outlined before, to have two sets of lights, but doncaster council dont seem to like having 2 sets of lights where they aren't seperated by an island, hence the odd combination.
This would be ideal:
I might email them with my proposal
