Walk, bike, take the bus, carpool, vanpool, car-share or ride the T.
Do not idle. It's the law, and it saves gas. Restarting the engine uses about the same amount of gas as idling for 30 seconds.
Stick to the speed limit and avoid rapid acceleration. Driving 55 instead of 60 raises your gas mileage by about 5 percent.
Check your air filter. Replacing a clogged air filter can improve your car's gas mileage by as much as 10 percent.
Maintain your engine regularly. An improperly tuned engine wastes gas.
Keep your tires properly inflated. Under inflation of just 1 psi in all four tires lowers your gas mileage.
Lighten your load by emptying your trunk of unnecessary items. An extra 100 pounds in the trunk reduces your gas mileage by 1-2 percent.
Optimize your route by combining errands and taking shortest route.
Remove roof racks to reduce aerodynamic drag.