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Climate Change Contacts

Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Climate Change in the Pacific Southwest
— Transportation

Fuel Efficient Vehicles and Alternative Fuels Smart Choice Guide:
Driving and Maintenance Practices

Smart Choice Fact

Gas mileage usually decreases rapidly at speeds above 60 mph. Each 5 mph you drive over 60 mph is similar to paying an additional $0.24 per gallon for gas. Observing the speed limit will save you $0.19 to $0.61 per gallon of gasoline.

EPA is responsible for providing fuel economy (gas mileage) data that is posted on the window stickers of new vehicles. These fuel economy estimates help consumers compare the fuel economy of different vehicles. Fuel economy data is also used by:

  1. U.S. Department of Energy (DOE) to publish the annual Fuel Economy Guide Exiting EPA (disclaimer)
  2. U.S. Department of Transportation (DOT) to administer the Corporate Average Fuel Economy (CAFE) program, Exiting EPA (disclaimer) and
  3. Internal Revenue Service (IRS) to collect gas guzzler taxes Exiting EPA (disclaimer)

EPA and the Department of Transportation’s National Highway Safety Administration (NHTSA) proposed an historic National Program that would dramatically reduce greenhouse gas emissions and improve fuel economy for new cars and trucks sold in the United States.


car engine

According to the Federal Energy Management Program (FEMP), preventive maintenance is one of the most cost effective ways to reduce fuel use. FEMP notes that preventive maintenance programs:

  • Increase cost effectiveness in many capital intensive processes and equipment
  • Provide flexibility for the adjustment of maintenance periodicity
  • Increase component life cycle
  • Generate energy savings
  • Reduce equipment and/or process failures
  • Result in an estimated 12–18 percent cost savings over that found in a reactive maintenance program

Regular vehicle maintenance makes fleet vehicles more fuel-efficient and reduces emissions.  Performing regular power-train maintenance including changing the air filter, changing lubricants with the recommended grade of oil, and keeping tires properly inflated can improve fuel efficiency by as much as 19%.  Cumulatively, regular maintenance can create substantial fuel economy benefits with relatively small inputs.

Fleet fuel tracking programs can help ensure vehicles are properly maintained and retrofitted or replaced when needed.  Fleet operators and monitor a fleet’s fuel economy by vehicle and class to determine when a vehicle is not running properly or if there is an emissions related problem.  In addition, tracking the total annual fuel usage is a relatively easy way to show measurable improvements in overall fuel efficiency and cost savings over time. 

EPA Region 9’s Auto Repair and Fleet Maintenance Pollution Prevention fact sheets provide complete environmental, technical and economic evaluations of pollution prevention ‘fixes’ for auto repair and fleet maintenance operations. 

Fuel-Efficient Driving Practices And Training

driving a car

As the primary users of fleet vehicles and equipment, drivers and operators are critical to successfully reduce fuel consumption and greenhouse gas emissions. Education and training for drivers and operators on methods to help optimize fleet efficiencies is an important step. As demonstrated below, driving habits can greatly affect fuel consumption and efficiency.

Quick acceleration and heavy braking can reduce fuel economy by up to 33 percent on the highway and 5 percent around town. New EPA tests account for faster acceleration rates, but vigorous driving can still lower MPG.

Excessive idling decreases MPG. The EPA city test includes idling, but more idling will lower MPG.

Driving at higher speeds increases aerodynamic drag (wind resistance), reducing fuel economy. The new EPA tests account for aerodynamic drag up to highway speeds of 80 mph, but some drivers exceed this speed.

Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Note: Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

Cargo or cargo racks on top of your vehicle (e.g., cargo boxes, canoes, etc.) increase aerodynamic drag and lower fuel economy. MPG tests do not account for this type of cargo.

Towing a trailer or carrying excessive weight decreases fuel economy. Vehicles are assumed to carry only three hundred pounds of passengers and cargo during testing.

Running electrical accessories (e.g., air conditioner) decreases fuel economy. Operating the air conditioner on "Max" can reduce MPG by roughly 5-25% compared to not using it.

Driving on hilly or mountainous terrain or on unpaved roads can reduce fuel economy. The EPA test assumes vehicles operate on flat ground.

Using 4-wheel drive reduces fuel economy. Four-wheel drive vehicles are tested in 2-wheel drive. Engaging all four wheels makes the engine work harder and increases crankcase losses.

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