We had to go past there tonight, and I think I saw 3 induction loops in the right turning lane, so if there is a queue building up then even if you block the one nearest the light the other two (if there are enough cars) should be triggered.
The three loops are a standard "detection" set up, usually at 12, 24, &39 mtrs from the stop line they work on the same induction principal but perfom a slightly different role and the best way to be "seen" is as said ride over the loop edges themselves [if you can].
On final thing, if the loops are damaged and the "controller" no longer " sees a detection input it will usually assume a permanent demand, therefore the side road will be permanently coming on. Not so hot if you want to go straight on. If just one loop is damaged it may be written out of the programme on a temporary basis by an engineer untill the loop can be "recut" a messy job involving blocking the lane, so try and hit all the loops if you can, just in case.
