Green Travel Advice

A scientists' group has put together a guide to green travel to help you determine which modes of transportation have the smallest carbon footprint, and the group, the Union of Concerned Scientists, says some of the greenest choices can also save money.

UCS researchers compared the amount of carbon dioxide — the chief heat-trapping gas that drives global warming — from driving, flying, traveling by train or bus, and also compared per-person emissions for solo travelers versus those traveling in pairs or as a family of four. Here are some of their findings:

—For trips of more than 500 miles, if you're traveling solo or with one other person, it's greener to fly direct in coach than to drive, according to the UCS.

—First-class seating takes up more space than coach seating, so the average first-class passenger on a domestic flight is responsible for generating twice as much carbon as someone seated in coach, UCS says. Budget airlines with no first-class seats can lower a plane's per-person emissions 10 to 15 percent.

—Compared with flying coach, a couple traveling on a bus will cut their trip's carbon dioxide emissions 55 to 75 percent, depending on the distance traveled. Compared to even a fuel-efficient hybrid car, a bus trip would cut a couple's trip emissions nearly in half. Bus travel is usually less expensive than flying and for a solo traveler, can be cheaper than driving.

—Trains emit 60 percent less carbon per passenger-mile than a typical car with a single occupant. And compared with a 500-mile trip on a small jet plane, a train emits roughly 30 percent less carbon. Trains also can save money by dropping you in city centers, so you don't need to get a taxi or rental car to get into town.

—The type of car you use for a road trip makes a big difference. An SUV emits nearly four times the amount of carbon dioxide emissions of a highly efficient hybrid such as a Toyota Prius, and uses nearly four times the amount of gas.

—Traveling off-peak can also lower your carbon footprint and travel bills. Spending less time in traffic means better mileage and lower fuel bills; flying off-peak means your plane won't be wasting fuel in a holding pattern and your ticket could be cheaper.

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Copyright 2009 The Associated Press.