The next time you find yourself renting a car or calling for a cab, ask whether a hybrid or other low-emissions vehicle is available. Increasingly, rental car companies and taxi services are providing such vehicles in their fleets, and some (in major cities) offer exclusively green options. Consider it an opportunity to take a hybrid (or other eco-vehicle) for a test drive. If you can’t find one that’s available where you are, at least make sure to get a compact car (or whatever size is adequate for the number of people in your group). There’s generally no need to get a gas-guzzling SUV, van, or limo if you’re shuttling around fewer than 5 people. If you’re renting a car and the representative offers you a larger vehicle for the same base price, keep in mind that you’d pay more for gas to run the larger vehicle, you’d be producing more air pollution, AND it would be harder to park.