"Decrease your speed. Gas mileage usually decreases rapidly above 60 mph. Each five miles per hour over 60 mph is like paying an additional 20 cents or more per gallon for gas.
Drive sensibly. Speeding, rapid acceleration (jackrabbit starts), and rapid braking can lower gas mileage by 33% at highway speeds.
Use cruise control and overdrive gear. Cruise control cuts fuel consumption by maintaining a steady speed during highway driving. Overdrive gear, when appropriate, reduces engine speed, saves gas, and reduces engine wear.
It’s a “drag.” Avoid carrying items on your vehicle’s roof. A loaded roof rack or carrier increases weight and aerodynamic drag, which can cut mileage by 5%. Place items inside the trunk when possible to improve fuel economy.
Turn down the AC. Operating the air conditioner on "max" can reduce mpg by 5-25% compared to not using it.
Avoid idling, which gets 0 mpg. Cars with larger engines typically waste even more gas while idling than cars with smaller engines.
Fill up before returning rental. Rental car companies charge higher gas prices if you don't fill up the tank before returning the vehicle."
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