Avoid quick starts and aggressive driving:
Flooring the gas pedal produces high pollution rates and wastes gas. One second of high-powered driving can produce nearly the same volume of carbon monoxide emissions as a half hour of normal driving, according to the American Council for an Energy-Efficient Economy.

Stick to the speed limit:
Driving 65 mph instead of 75 mph will improve your fuel economy by about 10 percent and will decrease tailpipe pollution in many vehicles. A leading consumer magazine found that slowing down from 75 mph to 65 mph resulted in a five-mile-per-gallon performance increase, and slowing down from 75 mph to 55 mph saved 10 miles per gallon.

Avoid hard breaking:
Especially in traffic, try to anticipate stops rather than breaking hard. This will prevent increased pollution, wasted gas and wear on your breaks.

Use an electronic toll collection system: 
Budget e-Toll^TM avoids cash payment lines at toll booths. Studies have found that paying tolls electronically reduces hydrocarbons and carbon monoxide emissions by 40-63% and reduces emissions by 16%.

Try to avoid rush hour:
Stop-and-go driving burns gas and increases emissions of smog-forming pollutants. Plan your schedule to avoid driving during peak traffic times.

Always use a GPS navigation system:
Some systems, such as where2^® GPS navigation from Budget, provide real-time traffic alerts which help avoid traffic jams and road construction, and eliminates the extra driving that results when renters get lost. Anything that reduces unnecessary driving time reduces emissions — and saves you money on gas.

Open your windows before turning on the air conditioner:
Removing the hot air before turning on the air conditioning will reduce fuel consumption and nitrogen oxide emissions in some vehicles.

Don't warm up your car:
Newer cars have been designed to operate effectively soon after start-up, even in cold weather.

Use cruise control:
Cruise control will help you maintain a steady, constant speed, which will reduce the need for acceleration and braking. Edmunds.com, a respected resource for automotive information, conducted a study which concluded that using cruise control reduced fuel consumption by 7%.

Try not to idle for more than one minute:
Idling your engine generates more pollution than driving, and it wastes fuel.