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There was a time when biking in the world’s cities was the domain of bike messengers and a handful of steely-nerved citizens. No more. From Barcelona, Spain, to Paris to Washington, D.C., bike-share programs are rolling full bore. Yep, they’re green, but they’re convenient too: Wheel door-to-door and let everyone else claw for parking. Just buy a pass online or at the bike station itself, and go. In Washington, D.C., $4.50 buys you a 90-minute spin around the city and the priceless satisfaction of pedaling past drivers stewing in traffic. (Tip: Short-term usage fees can add up, so renting by the day is often cheaper.) Here are some of our favorite spots worldwide for biking on the go:

Denver
This was the first U.S. city to launch a large-scale, citywide bike-share program. Buy passes online or at the B-cycle stations. (303) 825-3325, www.denverbikesharing.org

Washington, D.C.
Capital Bikeshare has more than 110 bike stands throughout the nation’s capital and neighboring Arlington, Va. (877) 430-2453, www.capitalbikeshare.com

Austin, Texas
If you’re looking to ride all day, renting a bike may be cheaper, and Barton Springs Bike Rental offers a fun twist: guided tours by conventional and electric bike. (512) 480-0200, www.bartonspringsbikerental.com

Chicago
B-cycle’s rental stations, available from May to September, are clustered along the lakefront. Buy a one-day pass for $20. (773) 672-2000, www.chicago.bcycle.com

London
Locals call them Boris bikes (after the mayor, Boris Johnson), but you’ll recognize them as Barclays Cycle Hire. Transport for London continues to build cycling lanes (superhighways) into central London. 011-20-8216-6666, www.tfl.gov.uk/roadusers/cycling/11598.aspx

Montreal
The Canadian city has some 400 BIXI stations that operate from April through November. This summer, BIXI also debuted in Toronto, Ottawa and Gatineau. (514) 789-2494, www.bixi.com