Lately its configuration is such that if approaching from one of the side streets and the light is red, you have to stop and wait for it turn green. This doesn't seem to be any better than an inductive loop in the pavement, and thus the current implementation is a waste of money (IMHO).
The reason 'they' do this (well, in the Netherlands) is; if local people grow accustomed to the fact that they can always count on the light being green when they are at the intersection, they will after awhile expect it to be green. By delaying the green, people will slow down before they have reached the intersection, which is safer.
Don't know if this is actually true, but it's the rationale given.