Is it better to leave a car running than turn it off?

A very common misconception people have is that it takes a large amount of fuel to start your engine.  Because of that often people will leave their cars running instead of turning them off when they are planning to sit idle for several minutes.  Depending on the type of car you have and the size of the engine, you will waste roughly one half gallon a fuel per hour while your car is idling.  This may not seem like much, but considering the cost of fuel, leaving your car when you are not moving can be very wasteful.  It has been so wasteful that in some areas people are starting campaigns to prevent people from doing this.  It is a simple way you can keep your wallet full and help the environment.