Make people aware what is bad about leaving their car engine running and stop the once you see. An idea from Yichun

I mean there are people stand their cars in a parking lot or on the street sides with engine running, heating/AC on with windows wide open, not just for 5 minutes wile their waiting. (could be waiting for anything also for the bridge to close or in front of the train track) Taxi drivers does this a lot while they wait for a customer for example.

And I don't always, actually never was brave enough to knock the window and talk to them. But I think people should change their idea about our surrounding sources, maybe there is a way that makes the world better but at the same time self convenient?

oeps accidentally clicked 'don't do this' but didn't want to.. I agree with you. total waste.

@Ingetje, I'll make it possible to undo a vote. Than these things won't happen anymore...

Restarting a car also cost some energy. In general: it's better to switch it off if you will be waiting longer than 30 seconds.

@Maarten, great! @bart, true...

I'm with Yichun, if I see it I get very annoyed but I never dare expressing my disapproval.

And yes Bart, of course one should also ask how big is the gain. One, maybe two minutes less in comparison with maybe skipping a whole car ride.

The gain is big if you consider taxi's that keep their motor running for quite a long time. That 30 seconds is actually a very short time (most traffic lights take longer!)
Modern cars switch off their engines automatically when in neutral (and they have a very economical starter too, so break even point is at 5 sec).

wow, 5 sec is short! didn't expect that. interesting information!
probably you got to have Prius for that

about the start-stop system: http://en.wikipedia.org/wiki/Start-stop_system

I told this to a guy once and he got so pissed that we almost got into a punch-up. Don't do it. Besides what's the use when stuff like grunt-phobos happen?