And bicycling isn’t just an inexpensive option for commuters, says Kate Powilson, with the national advocacy group BikesBelong. It’s a good deal for cities, too.

"Cities are realizing the benefits of bicycling, because in this economic climate, there's not a lot of money in budgets to build new roads and to expand light rail and subways," says Powilson. "And, so, bicycling is a really cheap way to move people."

And it doesn’t appear to significantly slow down traffic.

Bicycle commuting in America has more than doubled since 2000. In Philadelphia, more than 10,000 commuters choose pedal power to get to work every day, according to the Bicycle Coalition of Greater Philadelphia. That number is expected to grow during the summer months, especially if gas prices continue to rise. Last Friday was National Bike-to-Work Day. Mayors, officials and lawmakers in hundreds of cities across the country joined thousands of their citizens on two wheels, to highlight the popularity - and practicality - of bicycle commuting.