One of the biggest ways to reduce your gas bill is to stop speeding. On the highway, 93 km/h is the most fuel-efficient speed to drive. For every 10 km/h that you drive over this limit, you are burning up an extra 10% of your expensive fuel. The average speed on the highway seems to be around 113 km/h so every car is wasting 20% extra gas. But the speeding concept continues in city driving as well. Jack-rabbit starts, racing between red lights, and flying down backstreets to ‘make up time’ all can eat up an extra 15% of your car’s gas. Most people speed because they are late. Plan ahead and leave early, then you won’t have to speed.