SHUT IT OFF

Turn your car off

 When you turn on a car, it uses a bit of gas. When the car is idling, it uses a fixed amount of gas over a period of time (especially with the AC on).
In most scenarios (depending on the car), the energy balance will be positive if you turn off your car for more then 20 seconds.
That means you can save gas if you turn off you car while waiting at long traffic light sequences, railroad crossings or while your better half pulls money from the ATM. Any time you can foresee that you will not be moving for more then 30s or 1minute you should turn off the engine to help your vacation budget.