I read decades ago that anytime you're stopped for about 25 seconds or more, turn off the engine. Guess it's less than that. https://www.edf.org/attention-drivers-turn-your-idling-engines
So, if you're going to be in a line of several vehicles waiting to do something (gas, drive up windows, etc.), don't move up until you have to. Like if a vehicle is going to be stuck in the street. Moving up one spot, whenever the vehicle in front of you moves, is also a waste. How many of you who use drive through car washes actually turn off the engine while going through in neutral? Hmmmm? Since around the 80's, there's no need to go outside to warm up your vehicle. You're coming out a warm building, wearing clothing, and the vehicle will be giving heat within a mile or so. As long as you're driving within the local speed limits, the engine will be fine.
If one of the DCP threads goes off track a little about water savings, get back to me.