> the rare occasion when it doesn't work for whatever reasons

That's actually intentional (or at least I know for a fact that in some places it's by design). It keeps drivers alert and break the habit of just going ahead. Sometime for whatever reason the light has to be red and in some cases the public transport drivers were so used to just going through the intersection that they completely miss the lights. Also many of them get in their personal cars at the end of the day to the same effect. It's a known, studied effect and the solution is to "mix it up" a bit.