Not everybody has to have a car. There are a lot of opportunities to share rides with one other person or with a whole bunch.

Mass Transit

Mass transit helps reduce the number of cars on the road. Numbers vary, but the Maryland Department of Transportation estimates that a full bus eliminates sixty cars on the road and that translates to reduced emissions to the air and runoff to streams and creeks. You can find out more about the bus service in your area by contacting the local transit authority or by looking online for schedules and routes.

Taking the bus allows riders time to read, listen to music, even catch up on sleep on the way to work or school. Bus rides can also be substitutes for long car trips. Greyhound and Trailways buses travel across the country, allowing riders to check out vistas along the way. Before making a trip, ask about meal stops and consider bringing along a pillow and snacks to make the trip more enjoyable.

In 1994, the city of Chattanooga, Tennessee, was determined to correct its choking air pollution and traffic congestion and started a free shuttle service utilizing electric buses. Over half a million passengers ride the 3.5-mile route every year. Parking revenues and leasing of commercial space in parking facilities pay the operating costs for the buses. The cost to operate the electric fleet is about the same as a diesel fleet. Tune-ups and oil changes are unnecessary and maintenance costs are lower. Since that time, more cities are utilizing alternatively fueled mass transit systems.

In many larger cities, trains and subways are a popular mode of transportation. Commuters in the suburbs can park near their homes and catch a train or subway all the way into the city.

Sharing Rides

If you live in an area where riding mass transit isn't feasible but still want to take a car or two off the road, consider carpooling. A number of Web sites match destinations and drivers looking to save money and vehicle use. Check out sites like eRideShare.com, Carpoolconnect.com, iCarpool, and RideShareOnline.com.

Not only does ridesharing offer companionship and a break from always having to be behind the wheel, many states have carpool lanes. These high-occupancy vehicle lanes allow cars to sidestep traffic for a less congested ride.

Depending on how long the commute is, riders may be spending a lot of time together, so it's best to set a few rules at the get-go:

• Where will drivers and riders meet? Will it be at someone's house or a common location like a parking lot?

• Will anyone be smoking? Some people may not mind being around smoke if it's in someone else's car while others may choose not to expose themselves to smoke at all.

• Is eating in the car okay?

• Are stops acceptable?

• Will there be a set wait time if someone is late?

Some Web sites allow rideshares to select criteria, filtering out certain elements. If everyone in the carpool drives equal miles, then the costs will be even. But if one person is the sole driver, the costs will need to be split. The American Automobile Association calculated in 2006 that every mile a person drives costs $0.52. This accounts for gas, insurance, and maintenance. So when one person drives more or is the only driver, it's fair to ask others sharing the ride to pony up.

Sharing Cars

Car sharing has increased as well, and there are a variety of programs available. Businesses like Zipcar operate in numerous cities across the United States, including New York, Chicago, and Los Angeles. Cooperatives like City Carshare in San Francisco operate as nonprofits.

With car-sharing programs, members pay a monthly fee or hourly rates and have access to a variety of cars and trucks. You choose whatever vehicle suits your fancy, a truck for that trip to the lumber yard or a sedan for a night out with friends. Most programs offer a fleet of hybrid and low-emission vehicles, too.

Estimates for the number of personal vehicles taken off the road for each shared vehicle range from four to ten depending on how many people share the car. Car sharing encourages people to drive more efficiently because they're either limited to hours offered by their plan or paying for each hour. Costs of the program include gas and insurance (and sometimes perks like XM Radio) and members don't have to bother with parking their own car or taking it in for repair work.