Try to reach lights when they turn green. Keep enough space between you and the car in front of you so that you can accelerate gradually without closing the gap. Brake gradually when preparing to stop. Minimize the need to brake by anticipating traffic conditions. Travel at moderate speeds on the open road.
Higher speeds require more gasoline to overcome greater air resistance.
Slower speeds create a traffic hazard. When you reduce gasoline consumption, you save money and time. In the process, you also conserve energy.