That's not to say that biking doesn't come with risks. Without the protective steel casing of a car, bikers are vulnerable to being hit by distracted drivers or "doored" — knocked off their bikes when someone exiting a parked car unwittingly opens the door into their path.
But even as bicycling is becoming a more popular way to get around, the number of bicyclists injured in crashes with motor vehicles declined 10 percent nationwide from 2014 to 2015, according to the most recent data available from the Department of Transportation. The number of deaths rose 12 percent, but fatalities among bicyclists remain relatively rare. In 2015, 818 U.S. bicyclists died in accidents with motor vehicles, accounting for 2 percent of all traffic fatalities.
The worst cities for fatalities that year were Albuquerque, with nine deaths per million residents; Tucson, with 7.5 deaths; Las Vegas, with six; and Phoenix, with five. In the District, there were about 1.5 bicycle fatalities per million residents, about the same as New York City. That makes the nation's capital — where city officials have pushed to improve biking infrastructure — among the safer cities to bike.
But what about the health effects on bicycle commuters riding on exhaust-filled city streets, where they inhale more air pollution from cars, buses and trucks than their counterparts who commute in vehicles and can close their windows?
A 2016 study published in Preventive Medicine suggests that in all but the most polluted parts of the world, the health benefits of biking far outweigh the adverse affects of injuries and of breathing in tiny particulate matter (from car exhausts, among other sources) that lodge deep in the lungs and increase the risk of respiratory diseases and even lung cancer.
Researchers in 2010 found that injuries can subtract five to nine days of life from the average adult cyclist, and air pollution can subtract from one to 40 days, but the benefits of cycling can add three to 14 months to a bicyclist's life.
"The benefits of active travel outweigh the health risk of air pollution exposure and accident risk by far. The benefits of physical activity are just so overwhelmingly large," said Hanna Boogaard, an epidemiologist with the nonprofit Health Effects Institute, who worked on the 2010 study.
"However, as a cyclist, if you want to reduce the air pollution exposure and accident risk and you have the possibility, we always recommend to avoid busy roads, and taking smaller roads, even if that would prolong the trip a little bit."
That the cost-benefit analysis would favor biking makes intuitive sense to Brian Flanagan, who cycles 24 miles each way between his home in Haymarket, Va., and his office in Chantilly, a ride that takes about an hour and a half. He has noticed the effects of his commute not only on his physical well-being but also on his mental and emotional state.
"I'm much more excited and ready to start the day when I get to work, as opposed to sitting in traffic for an hour," Flanagan says. "Going home, I tend to go a little slower, more relaxed. By the time I get home, I'm in a better mood to hang out with the kids."
But you don't have to bike nearly 50 miles a day — or even close to that far — to realize the benefits of traveling under your own muscle power. You also don't have to be wealthy. You just have to change your routine (though it also helps to have access to a locker room at work).
In interviews with The Washington Post, six bike commuters described how they came to travel on two wheels and why they persisted. Most said that biking had, in the long run, saved them money; most said they showered at work to make themselves presentable during the hottest days of summer; and all of them said they liked how biking built exercise into their day.
The proportion of Americans who bike to work quadrupled from 2000 to 2015, from about 1 percent to more than 4 percent, according to census data.
While there's still a lot more work to do to improve bicycle infrastructure and safety, says Gregory Billing, executive director of the Washington Area Bicyclist Association, "bicycling is definitely growing in the region."
Route: Takoma Park to downtown D.C., 16 miles round trip
Bike: Raleigh Misceo iE electric bike
World Bank economist Tricia Koroknay-Palicz started using a bicycle to get around in the third grade, when her father would lead her and her two siblings on a three-mile trip to school. "It's such a gift my dad gave me," she says. "We'd follow him like little ducklings, and he taught us how to ride safely on city streets."
As an adult, biking has become a critical part of her day. When she and her husband moved from Georgetown to Takoma Park, she relished the longer ride to her office downtown. "It clears my head," she says. "It's exercise, there's sunshine and it's really cheap. It makes me happier."
But in recent years she went through four pregnancies, three of which ended in miscarriage. She felt sapped of her usual energy. And so when her boss bought an electric bike, she was inspired to explore doing the same. In February, 36 weeks pregnant, she bought a used electric bike — and it changed everything.
Even when walking became uncomfortable in the last weeks of her pregnancy, she could continue to bike with ease, turning the level of electric assistance up or down, depending on how she felt. In late pregnancy and right after her daughter was born, she often rode with the highest of three levels of assistance; now, she usually rides on the middle setting. She rarely turns the e-assist off completely, and when she does, it's a workout: The e-bike is more than twice as heavy as her regular road bike.
Back at work now, Koroknay-Palicz bikes in a T-shirt and shorts, carrying her work clothes and lunch in panniers. Her computer and journal get packed inside a dry bag to protect against downpours. And she gets to work without sweating, traveling nearly as fast as a car.
The Bowen Family
Ages: Monroe, 5; Dalton, 8; and their parents,
Brigham Bowen and Jennie Dalton Bowen, both 41
Route: It's complicated
Bike: Capital Bikeshare and Yuba Mundo longtail, a cargo bike with a seat in back that can fit two children
The family lives on the east side of Capitol Hill, the kids go to school at Mundo Verde, a charter school two traffic-choked miles away in Bloomingdale, and the parents both work downtown. So Brigham Bowen and Jennie Dalton Bowen depend on bikes — and occasionally buses — to make their commute work.
"It's faster and it's easier," Brigham says.
To an outsider, it doesn't sound easy: Brigham leaves home each morning with the two boys on the back of a Yuba Mundo longtail, and they weave about 2.5 miles through neighborhoods to get to school. After drop-off, Brigham cycles to his office near Union Station, where he parks the bike.
Jennie takes Metro to her office on K Street. In the afternoon, she uses Capital Bikeshare to get to Union Station. There, she unlocks the family bike and rides it to pick up the boys at school. They cycle home, and Brigham takes the bus.
The Yuba Mundo cost about $2,000. But it suited the family's needs well and was enough of a commitment that it has helped encourage them to stick with their multimodal commute. "Once we invested in the bike, it then became the easy choice," Brigham says. "Once we had the gear, it was easy to just throw the kids on the bike and not have to deal with cars and feel good."
Route: Petworth to College Park, 16 miles round trip
Bike: Kona Jake the Snake
Andrew Smith's rent payments climbed when he moved from the suburbs into the city. As a University of Maryland graduate student on a budget, he needed a way to save money, so he became a dedicated bike commuter, cycling most days from his home in Petworth to his office in College Park.
He wasn't a stranger to biking. He'd been tooling around College Park for a couple of years, but rarely more than a mile or two at a time. He learned bike maintenance and repair skills at the Bike House, a cooperative in Petworth.
And with a new and more demanding daily ride, he upgraded to a nicer bike. But he didn't buy much more than that.
"I'm a super minimalist," he says.
He carries a clean shirt — and that's about it. He used to travel with a backpack full of clothes, but his adviser walked into his office one day and asked what smelled so funky.
In the summer, he bikes in a T-shirt and shorts, and he showers at work. In the winter, he wears wool gloves and layers that he can shed as he warms up. And year-round, he wears padded bike underwear.
"Sometimes," he says, "the saddle can be kind of hard on your butt."
Route: Bethesda to downtown D.C., 25 miles round trip
Bike: Trek Verve 2
Lawyer Carol Calhoun started slowly, biking once a week to breakfast with a friend. Then she started biking from her home in Bethesda to the farmers market in Dupont Circle. And so when she landed a new job downtown, she figured she could make it there on two wheels.
Now she's a bicycle commuter, riding almost every day and so committed that she has tire chains so she can keep cycling in snow and ice.
"If you're driving, you've got to deal with traffic jams and the time it takes to park. If you're taking public transit, buses don't always come when they're supposed to," Calhoun says. "Ultimately, it just seemed like biking wasn't that much different in terms of time, and I was getting a couple of hours of exercise a day."
Most of her route is on the Capital Crescent Trail, away from cars. But she often bikes at night, so she has invested in good front and back lights to make sure she can see and be seen in the dark. She also wears a combination video camera and headlight on her helmet, so she has a record in case she's hit by a car.
But she doesn't wear fancy bike clothes, and she doesn't think anyone should be deterred from biking because they think they need to buy a bunch of extra gear. In winter, she wears the same layers she would wear out walking, topping off with a down jacket on a particularly cold day.
"Basically, if you start out with a bike, some lights and a U-lock — and maybe something to carry things in — that's all you need," Calhoun says.
And you don't need to be a fitness guru to start biking, she says, recalling how she built up her endurance over time. You can bike one way or part way to work, or once a week. "I think a lot of people have this idea that 'real cyclists' will look down on them if they only bike some of the time, or only for short distances," she says. But "there are no 'real cyclists'; there are just people who put on their clothes and get on a bike."
Route: Arlington to downtown D.C., 18 miles round trip
Bike: LeMond Nevada City
Carlos Goldie used to weigh 320 pounds. Now, he clocks in between 240 and 250. It was the death of his father four years ago that prompted him to start exercising more and lose the weight — and it is biking that has helped him keep it off.
"I started one day a week, two days a week," he said. As Metro became increasingly unreliable, and he grew to enjoy biking more, he ramped up his two-wheeled commute to almost every day.
"I had a SmarTrip card with $190 on it. I gave it to my sister," he says.
At the same time he was getting more serious about bike commuting, he completed his first century ride, the 100-mile Bike to the Beach benefit for children with autism, an annual ride from the District to the Delaware shore. He was hooked. "After that, I just never got off the bike," he says.
In the morning, he rides about 6.5 miles from his home in Ballston across the Key Bridge and through Georgetown to get to his office downtown, where he works as a paralegal. In the evening — when Georgetown's streets are more choked with traffic — he takes a longer way home, crossing the Potomac River on the 14th Street Bridge and then hooking up with the Mount Vernon and Washington & Old Dominion bike trails.
When he started bike commuting, he'd put his work clothes in a backpack and lay out his gear the night before so he didn't have any excuse not to ride.
He also kept a spreadsheet to track the money he saved on Metro fare: close to $7 each day. It was motivating to see the numbers add up. He estimates he has saved at least $7,000 so far.
Route: Capitol View in Southeast D.C. to Navy Yard, 13 miles round trip
Bike: Fuji Declaration single speed
Synta Keeling lives in the District's far southeastern corner, in a predominantly low-income neighborhood known as Capitol View. She views biking — including two or three times a week to the Navy Yard, where she works as a lawyer for the federal government — as a political act.
There isn't much in the way of biking infrastructure in her neighborhood, Keeling said. Grocery stores and other amenities are few and far between, and work for many people is across the Anacostia River, requiring a longer ride that can be intimidating to prospective cyclists.
Keeling — who has to ride on the sidewalk part of her way to work — wants to show that biking is nevertheless an option.
"When you're out on your bike, it's like a walking billboard for health and for the environment," she says. When you drive a car, you're burning fuel. When there are delays on Metro, you're burning time. "But when you're on a bike, you're burning fat — and you can go wherever you want," she says.
Two-wheeled transportation also clears her head and knits the city together for her in a way that driving does not. It's easier for her to make pit stops on a bike — to run errands or meet friends — than it is when traveling by public transit or car. "The more that we do it, the more we make D.C. neighborhoods feel like connected communities," she says. "You will see the city in a way you've never seen it before if you just get out on a bike."