There was a brief period, from around 1880 to 1908, when bicycles were ascendant in American cities. By 1896, around 2.5 million bicycles were on the streets, and bicycle clubs were forming to advocate for safer roads. After the horse, the bike was the first real form of private transportation, and it became wildly popular with the middle and upper classes. As The Bookman chronicled in 1901: “The great avenues of our larger cities were made extremely picturesque in the dusk of evening by the endless line of bicyclists whose lanterns in the darkness produced the vivid effect of a river of coloured fire.”

That all changed when Henry Ford started cranking out the Model T in 1908, stoking Americans’ almost inexorable passion to drive—to work, to the grocery store, to their kids’ soccer practice. In 1971, the average American traveled around 5,600 miles annually by car. By 2005, that number had nearly doubled, to 10,100 miles. There were a handful of dips, like the 1970s oil embargo, but the trend was steady for the 20th century: Each year, the national odometer climbed higher. Our communities and streets, once designed for pedestrians—and briefly, for the bike—became focused on accommodating the automobile.

And then something puzzling happened in 2006: Americans drove fewer miles than they did in 2005. The same thing happened in 2007, and every year since. By 2013, Americans were driving 7 percent fewer miles than they had in 2005. What happened?

A number of factors are behind the drop, including the economy-decimating repercussions of the Great Recession and higher oil prices. The economic free fall, though, didn’t begin until 2008, while the mileage started dropping two years before. Beyond the economy, there is a broader shift taking place: Americans, especially Millennials, are moving to cities and leaving the car behind. Instead, they’re taking public transportation, walking and—almost unbelievably—bicycling.

Consider: Over the past 13 years, the number of Americans regularly biking to work has increased a stunning 62 percent. During that same time period, the United States has invested somewhere between $11 billion and $12 billion in bike infrastructure, including 50,000 new miles of bike trails, protected paths and lanes—enough to circle the globe twice. Just since 2011, there has been a 10 percent increase in Americans biking to work. “Populations in cities are growing, and people are more interested in easier and more active modes of transport,” says Sarah Kaufman, an assistant professor of planning at New York University’s Rudin Center for Transportation. “Bike commuting is a great way to get around.”

Why Ride?

The advantages of commuting by bicycle are plentiful. The most obvious benefit is health: Unlike drivers, bikers are actively exercising on their commutes to work. Not surprisingly, several recent studies have shown that longer car commutes are directly correlated with increased levels of obesity, larger waistlines and higher body-mass indexes. One 2009 study at Brown University, in fact, found that every minute spent driving to and from the office resulted in reduced time on essential health habits—sleeping, exercising and cooking food. A 10-mile round-trip commute in the city would likely take around 45 minutes, which means that a biker would reduce or eliminate the need for a trip to the gym after work. One 2010 study out of the Netherlands found that replacing a daily car commute with a bicycle would result in a life that is 3 to 14 months longer. Conversely, several studies have found that long car rides to the office are highly correlated with obesity and higher blood pressure.

Next up: cost savings. According to AAA, the average car owner will spend $8,876 on owning, fueling, insuring and maintaining a car over a single year. The average annual cost to own and maintain a bike? Just $308. You can reduce your costs even more if you participate in a bike-sharing program, which now exist in more than 40 American cities (see “Take a Bike, Leave a Bike”).

Then there’s speed. Yes, that’s right: Biking to work can often be faster than driving. Bike lanes and trails don’t experience the type of congestion that urban streets and highways do—the average urban American car commuter sat in a total of 38 hours of congestion over a year in 2011. One study from Lyon, France, found that bike commutes during rush hour were faster than driving, which supports anecdotal evidence across many American urban areas.

All these benefits don’t accrue just to individual commuters. The environment sees lower amounts of carbon emissions and lower air pollution. Transportation departments will spend less on road maintenance, because bikes cause much less damage to streets than automobiles. And with people on two wheels instead of four, car traffic will go down. Businesses benefit, too: A recent study in Portland, Ore., showed that bicyclists spend more money over a month than motorists at restaurants, bars and convenience stores.

“Everyone driving doesn’t make sense—using a 1,500-pound machine to move a 150-pound person,” says Peter Furth, a traffic engineer at Northeastern University in Boston. “Cities that go that route just get flooded with cars. And public transportation is really expensive to provide.” The answer: the humble bicycle.

Wheels and Woes

Challenges to bike commuting, of course, remain. Education is essential for bikers and drivers. Cyclists far too often run red lights and stop signs, or engage in dangerous behaviors like “salmoning” (riding the wrong way up a one-way street) or riding on the sidewalk (which is illegal in most cities and dangerous to pedestrians). Motorists, meanwhile, make the streets perilous for bicyclists by either not paying enough attention (making right turns in front of cyclists; parking in bike lanes; opening doors into the path of cyclists) or by acting downright aggressively.

The largest problem facing bike commuters, though, is the lack of a strong bike infrastructure. In many communities, bikers have to ride on streets loaded with automobiles; at best, a street may have a painted share-the-road “sharrow” or a bike lane. Unfortunately, says Furth: “The number of people willing to ride where you have to compete with cars in heavy traffic is very limited. Bikes have to be given a place where they are protected from heavy traffic.” Tim Blumenthal, the president of People for Bikes, a bicycle advocacy group, agrees: “If the only thing separating high-speed cars and bikes is a white line, the majority of people will not feel comfortable. If we want biking to really grow and thrive, we need more than white lanes on pavement.”

To entice a more diverse group of people to bike—especially women, older people and children—bike routes must be physically separated from cars. Trails along rivers or on the former beds of railroad tracks are widely popular for that reason. Another option is to separate bike paths from street traffic by placing parking spaces between the two; bikers can then ride between parked cars and the sidewalk. Other cities have seen success with a small concrete median, or even placing flex-posts on the street. Experts advise joining bicycling advocacy groups, especially those on the local levels, which can push for bike-friendly road improvements.

A study from University of Portland showed that separated lanes in Portland, San Francisco, Austin, Chicago and Washington, increased ridership in those cities between 21 percent and 171 percent. The same study found that two in three residents say they would be more likely to bike if lanes were separated from traffic.

Spin Cities

In the 1960s, Davis, Calif., made a remarkable decision: It was going to start investing transportation money on bicycle infrastructure and began to experiment with bike lanes. That initial investment paved the way for the city of 75,000 to become the bicycling capital of America: Today, 95 percent of streets in the city have bike lanes, and nearly 20 percent of all residents commute by bike. Almost unbelievably, there are now more bikes than cars in the community. Other cities have followed Davis’ lead: Boulder, with roughly 100,000, boasts 12 percent of commutes by bike, followed by Palo Alto, Calif.; Eugene, Ore.; and Cambridge, Mass.

Larger American cities are beginning to get in on the act. Portland, Ore., decided in the early 1990s to improve bicycle infrastructure, and today, 6 percent of the Portland workforce commutes by bike, which is the highest share for any large city. Closely trailing it are Minneapolis, Seattle, Washington and San Francisco.

Bicycle infrastructure takes a bit of money, but not an unearthly sum. According to Furth, the American government, on the whole, spends around $1.50 per person on biking infrastructure, compared to $400 per person on highway infrastructure annually. No one is calling for equalizing those spending levels. Says Furth: “Spending about $20 a person a year [in a city], over a 10- to 20-year period, could create a great bike network.” Consider the example of Portland, which has spent around $60 million building its bicycle network. That’s a good amount of money, but as former Portland Mayor Sam Adams pointed out in 2011, that entire bicycle network costs around the same as one mile of a four-lane urban highway.

Many local governments are starting to realize the exponential benefits of bicycles—not just for improving traffic, health and the environment, but as a competitive edge. “People in their 20s and 30s are not buying cars and driving at the same rate as their predecessors,” says Blumenthal. “They want to live, work, shop, party, and do everything in a convenient, close-by space.” And college-educated young people working in technology, business and medicine are the exact type of people who can help create a thriving city. “Cities want to attract dynamic businesses that depend on highly educated and motivated workers,” says Blumenthal. “They want to be able to ride to work and to go out to lunch and to recreate. These workers want a bike-friendly place.”