Engine off at lights if you know it will take longer than 10 seconds. Someone did a study that said restarting a gas engine was equivalent to 6 seconds of idling. Otherwise, shift into neutral and idle.
Practice P&G in an parking lot if there is one near you and a road is not available. Also remember that not all automatic transmissions like having the engine off while you shift into neutral. Check your owners manual just to be safe.
Mostly city eh? I don't know if P&G will be all that useful (unless there are that many opportunities for coasting). I just go with most pulse-n-gear coast to get the benefits of the deceleration fuel cut off. My current MPG is into the 40s thanks to that.
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