Hmmm.
In Chelmsford one of the town councillers got held up by the lights for 5 mins at the Army and Navy roundabout (which is on the main route into the towm/ station/ bus station/ Main Royal mail sorting office for east anglia/ two large industrial estates etc) and so had them turned off. Now 5 mile tailbacks are common and it can take up to an hour to get across it at rush hour!
I guess it depends on the situation.