I'd like some of our engineers working in the Automotive and road transport systems industry to settle an argument I've been having with my partner for some time now.
He's convinced that flashing your headlights at the temporary traffic lights you see controlling traffic flow at roadworks causes them to turn green. Now I understand his thought process in that there are sensors there that will 'see' there's vehicles waiting but I don't think that flashing your headlights makes any difference at all?
For example one evening last week (it was still daylight) we were out and about and while driving through a local village we came across some roadworks. As we approached the temporary lights you could see that there were no cars waiting on the other side so he starts flashing our headlights and in a few seconds the lights turn green. Now he's convinced that they turned green because he was flashing the headlights whereas I pointed out that 30 seconds before there were two cars travelling in the opposite direction from us that would have just gone through the lights. The fact that they turned green when we got there was purely because we had hit the sequence at the right moment. He on the other hand is convinced that flashing your headlights at them will turn them green if there are no other cars coming through.
So what is the answer? Does it or does it not? 
