Marc Breslow

Director of Transportation and Buildings Policy, Executive Office of Energy and Environmental Affairs

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As we head into the summer driving season, you can cut your gas costs by a quarter or more, and emit less pollution, by “smart driving” – maintain your car well, keep to the speed limit, accelerate less, and idle only when necessary. Every gallon of gas emits about 20 pounds of carbon dioxide, the main cause of global warming.

The U.S. energy (DOE) and environmental (EPA) agencies estimate that you can cut gas use 8% to 9% through good maintenance practices. These include using the recommended grade of oil, tuning your engine and replacing air filters at the proper times, and keeping your tires inflated correctly. Just having the right tire pressure can save up to 3% of your gas. You can also save on gas by buying tires that have higher efficiency. While at present there is no central source for finding such tires, some manufacturers have models that they market as being high efficiency – search for them on the web.

For the greatest savings, follow the example of the office supply chain Staples, which reports that it has cut diesel fuel use on its nationwide fleet of delivery trucks by more than 25%, through limiting their speed and acceleration and minimizing idling time. The graph shows how miles per gallon (MPG) varies with speed – you get the best MPG between around 40 to 60 miles per hour, with gas use increasing rapidly at higher speeds. Accelerating quickly and braking hard also uses a lot of gas. Driving more gently will save you money.

A few other easy ways to improve MPG:

• Don’t store extra weight in your car.

• Remove unused roof or rear racks.

• When using air conditioning, use the “recycle inside air” setting, so that the car does not have to continually cool hot outside air.

• Don’t keep the car running (idling) unnecessarily.

The Mass. Department of Transportation’s (MassDOT) Smart Driving brochure is here. 

If you’re in the market for a new or used car, remember that MPG varies widely, even for similarly-sized cars.

Of course you can also save gas by getting around through other means than one person in a car. Information on carpools and vanpools is available through MassDOT’s MassRIDES program. Or, check out Info on public transit for the Boston metro area , regional transit systems throughout the state, and bicycle trails.