I was told that if you are going down the highway and you notice you car is overheating, you should pull over but do NOT shut your car off. This does not seem right. Wouldn't your car sit in idle and overheat as well?
at highway speeds you're getting a LOT of air cooling for the engine, unless you're following someone too close and you're getting hot, "dirty" air. if you do some driving in town, let the engine get hot, you'll notice it sits just a tick below half on the gauge. get on the freeway and as soon as you turn on the cruise control it's down to just a tiny tick above the 2nd bar. get off and it goes right back up.
i would think that if you overheated while getting all this additional cooling, which might be in the neighborhood of 25+ degrees, you have a SERIOUS problem and you'd want to shut down as soon as you can. turn off the a/c and turn the heater on full temp/full blast if you need to limp it one more exit or something. but i wouldn't idle it on the side of the road.