09/13/2009 05:12 am ET | Updated May 25, 2011

Green Your Driving Habits: 4 Tips

I know, I know: It's better to take public transit, or to walk or bike, than to drive. But for those times when motoring simply can't be avoided, recall these four tips about ways to minimize your vehicle's impact on the planet.

1. Lighten Up. A free, easy way to reduce fuel use -- and cost -- is to make sure your car's not carrying any extra weight. Haven't cleared out that trunk or back seat in a while? It's time: Carting around an extra 100 pounds can reduce MPG by 2 percent. If you've got a roof rack, consider removing it or storing gear in the car instead to reduce drag.

2. Drive Sanely. Not only does aggressive driving aggravate others, it also wastes gas. To prevent excess pollution (and to preserve others' positive moods), drive within the speed limit, accelerate and brake gradually, and use cruise control on highways. Driving in a too-fast, herky-jerky way can lower gas mileage by 33 percent. Plus, your zen-like lack of road rage will clear the streets of psychological pollution too.

3. Don't Idle. Idling is one of the worst wastes of gas, especially in bigger cars. If you'll be stopped for more than 30 seconds, kill the engine; restarting it burns less fuel than the idling. Also, instead of inching ahead in drive-throughs, be motor-savvy by parking the vehicle and going inside.

4. Tune In. To get your car's greenest performance, make sure it's all tuned up. That means inflating and aligning your tires, monitoring your engine, replacing your air filter and oil on time, and stopping leaks as soon as you notice them.