What do you do at red traffic lights?

nothing wrong with it, but that's six exhaust pipes you could be avoiding if you were beyond the traffic queue; and potentially six less cars to get past further up the road when they are queuing behind some other stationary motor traffic;

{scenario applied to my typical morning commute on quietish roads with lost of traffic lights..}

1. Six? There's only 1 vehicle in front of you. Unless you're sucking air straight from the pipe, if you hang back enough from the vehicle in from you, then you're not getting much in the way of fumes. The laws of entropy tell me these thing even themselves out.

2. If you're up front and not in a rush then you're hoping 6 cars pass you with the space and care you need. Assuming I have time on my hands I'd rather have 6 less vehicles pass me.