Much of this is due simply to the fact that few people live in a situation where carpooling is an easy enough option. Carpooling is a great idea, but it's very hard to find a good carpool. You often don't live near enough a coworker for this to be possible, never mind someone who drives close enough to your own job.

Many cities have terrible public transportation. I live in such an area myself. People don't like to ride buses and such because it takes such an extraordinarily long time to get a lot of places. That's not true in all places, but in enough of them.

Rising gas prices have made everyone more aware of how much driving costs. More people have been thinking about how much they drive and what they drive.

Cutting back on driving is difficult, but it can be done. I speak from experience, having spent the past several months having only one car between my husband and myself. It's tough, but possible for us as I work at home.

One of the big changes you can make to improve your driving habits is to get more efficient about running errands. If the store is close enough, walk or ride a bike. If not, make sure that you take care of your errands efficiently. Combine errands, make lists so that you don't forget anything and need to run back. Little things like that can make your driving habits more friendly to the environment.

Beyond errands, you can think about ways you can use your car less. If your employer has a telecommuting program, see if you can participate. Even working from home one day a week will make a difference.

Look actively for a carpool. Yes, it can be hard, especially since it makes going out for lunch harder, but it makes quite a bit of sense on both the environmental and the financial level.

If your area has a great public transportation system, why not take advantage of it? A good system doesn't take forever for you to get to work, and can save you the stress of driving yourself.

Changing your driving habits for the better is one of the little things you can do for the environment. It's not one of the easiest things, and generally means accepting some inconvenience, but it can also help you save money. The combined benefits make such efforts very much worthwhile.