With so much talk about biodiesel fuel, hybrids, and hydrogen powered cars, it may seem like you can't use your old car at all if you're concerned about the environment. While a lifestyle change is probably inevitable for all of us eventually, there are many things we can do until eco-friendly models make our gas-powered cars of today obsolete.

Of course, decreasing how much and how often we drive is the best solution for our ecological conundrum, but since most of us won't give up driving all together, consider the following five easy ways to decrease your car's environmental impact.