I get many interesting and sometimes obscure topic suggestions from readers, but it was the obvious one I received recently that gave me pause. As it showed, while I'd been chasing down exotic ways for people to make a difference, I'd ignored one of the best of all -- and for no better reason than it's such a hard sell.

The proposed topic, from a commuter rail conductor in the Boston area, is using public transit. With gas prices what they are today, I'm thinking the sell might just have gotten easier.

I know that many people turn their noses up at the idea of using public transit. While yes, it's true, some places have inadequate (or non-existent) service, many metropolitan regions have rather fine systems these days, particularly since federal policy changed to make financing easier. The fact that they're still not all they could be doesn't mean they aren't a very good option, especially for the daily commute. After all, driving to work on congested roads is no picnic. Nor is it particularly economical.

Many people complain that public transit is inconvenient. This makes sense when service is infrequent, vehicles are overcrowded or multiple transfers are necessary. However, the complaint is raised even when these conditions don't apply, which leads me to suspect that the real impediment is often the reluctance to do something new.

I have this reluctance myself. When I had to visit a hospital in an unfamiliar part of town recently, my first thought was to take the car, despite the fact that I rely almost exclusively on the subway for daily travel. Even after learning that the subway would let me off close by, I hesitated, still concerned about chimerical problems -- that I wouldn't know which way to walk when I got out or that the neighborhood would be dangerous. In the end, my better sense prevailed, and I had a quick and pleasant trip without incident. The only real hurdle turned out to be mental.

Public transit accounts for just over 1 percent of miles traveled in the United States, compared to 10 percent in Europe. The benefits of following in Europe's footsteps include:

Cleaner air - More than 125 million Americans live in areas with unacceptable, unhealthy levels of air pollution, 50 percent of which is due to cars and trucks. Public transit is far less polluting than travel by private vehicles, producing 95 percent less carbon monoxide, 90 percent fewer volatile organic compounds and about 45 percent less nitrogen oxide, per passenger mile.

Lower global warming gas emissions - Our carbon dioxide emissions are the highest in the world, and cars and light trucks account for 20 percent of our total. Public transit emits half as much per mile traveled as cars.

Greater energy independence - It takes half the energy on average in the United States to transport a person over a given distance by public transit as private vehicle. If we utilized our transit better the savings would be even more impressive. A full bus is six times more fuel-efficient than a single-occupant car, and a full train, 15 times more.

Better water quality - Accommodating our large and growing number of cars requires ever more roads, bridges and parking lots. Runoff from all those impervious surfaces pollutes our lakes, rivers and coastal waters.

Less habitat destruction - The less construction we do to support our car culture, the less habitat we destroy.

Saved lives - There are far fewer accidents, injuries and deaths associated with public transportation than private cars. For instance, according to the National Safety Council, it is 170 times safer to travel by bus than car.

Less roadkill - No one really knows how many animals are killed on highways each year, but it is thought to number in the millions. Fewer cars on the road means fewer deaths.

There aren't many steps you can take that will do as much good for the environment. And you might find other, personal benefits as well -- such as better health from the short walk to the bus stop or train and a greater connection with your community. In Manhattan, where I live, even the rich take the subway (including, famously, our billionaire mayor, Mike Bloomberg) simply because it's the fastest way to get to work.

—Sheryl Eisenberg

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IRS-approved. The IRS allows companies to offer employees tax-free transit benefits -- i.e., to subsidize employees' commutes by bus, train or vanpool in the same way they might subsidize parking. Companies that don't wish to offer these benefits can still set up an IRS-approved program that allows employees to use their own pre-tax dollars to pay for transit passes.

Touring by transit. One of the best ways to get to know a foreign city is by using its public transit. Not only does it give you a feeling for the geography of the place, it puts you in touch with the locals.

Underground showcases. Subway systems around the world feature striking art and architecture. In Buenos Aires, colorful murals line the walls. Moscow's stations, designed by the Soviets as "palaces for the people," are grand. Paris has its signature art deco entrances, and Bilbao, its glass-roofed ones. Stockholm calls its art-filled subway system the world's longest art gallery. Indeed, visits to many cities might be considered incomplete without a look at their metros.

The carless. Public transit isn't just good for the environment, it's essential for those who don't own cars, including many low-income people, youth and seniors. Without it, they lack access to school, health care and jobs.