Here I go again...It was long ago in a place called Wisconsin and my dad was walking outside on a cold Winter morning to start the car car to let it warm up.  I was probably 6 or 7 years old and eventually got in the car which wasn't warm at all. When I asked why it wasn't warm he said he was letting the car warm up to drive it.  So that's what I always assumed was the best thing to do.  That was then, this is now. 

According to AAA in an article on msn.com, there's no need to start your car to keep it from freezing; at least not any more.  Today's cars don't have carburetors so you don't need to warm them up on frigid days.  Also, if you run your car to warm it up but don't drive very far you run the risk of depleting the battery.  Like me you may want to warm it up just to get it warm for heat and defrost but it's not necessary to let it run to keep it from freezing.  You can get a block heater for that.