What has two wheels, runs on human energy and is red, pink, blue or any color in the rainbow? A bicycle.

You may have noticed that in recent years, the number of people who bike in and around the city has increased. More people bike to work, to the grocery store, to pick up their laundry or to go to the movies. There are more bike lanes, bike signs, bike shops and there is even a popular bike idea, Capital Bikeshare, that allows people to rent red bikes to get from place to place.

And the trend is not limited to adults. Kids are getting in gear, too.

“In the winter we walk, and the rest of the seasons we ride our bikes,” Olivia Steckler, 8, said one morning outside Capitol Hill Montessori at Logan, a public school in Northeast Washington where she’s a third-grader. She was wearing a bright yellow vest (so that people can see her when she’s biking), her bike lock key on a string around her neck, and a pink and purple helmet. She stood next to her purple and teal flowered bike, which featured a bell on the handlebar.

“It makes me feel happy,” she said about biking. It takes her brother Ben, 5, and her about 15 minutes to ride from home to school with their babysitter.

“I don’t try to get distracted, but I like to think about how [riding a bike] makes me feel — sort of like I’m flying because my feet are off the ground,” she said.

Getting there faster

Olivia is one of many kids in Washington, especially in the Capitol Hill area, who bike to school with an adult. Kids are biking on the roads, in the bike lanes and on the sidewalks. (Cycling on the sidewalk is permitted everywhere in the city except in the central business district, where a lot of people work.)

Jennifer Hefferan, whose job is to make sure D.C. kids get to school safely, said that more people are calling her to ask about bike safety for kids. She also said that a school requests more bike racks almost every day.

“It’s crazy. That’s the thing that is the best indicator. If you’re biking to school and you don’t have a place to park, I’m getting the calls,” Hefferan said.

In May, more than 100 Washington area schools participated in the second annual National Bike to School Day. Wednesday is International Walk to School Day, but many kids will bike that day, too.

By the time the kids at Maury Elementary School in Northeast start class, all 12 of the school’s bike racks are full. “We keep putting in more and more bike racks,” said Principal Carolyne Albert-Garvey. The railings outside the school on a recent morning were also lined with locked bikes.

Malia Weedon, 8, a third-grader at Maury, likes to bike because it’s faster than walking. It takes her about five minutes to get to school on her bike, which features a bell and a pink and purple basket. She’s been biking to school for a couple of years now and likes to race her little brother, William, 6. Biking, she said, “doesn’t tire you out as much as walking.”

Ava Pugh, 9, a fourth-grader at Capitol Hill Montessori, has been riding her purple bike to school for two years. “It’s a lot more fun than driving,” she said.

Feeling good

Biking helps people feel good. That’s in part because of endorphins (sounds like en-DOR-fins), which can be released in your brain when you exercise and make you feel happy. Biking also helps keep you fit. Doctors recommend that kids get an hour of exercise a day, and biking is a great way to spend that hour.

“I’m getting muscles in my legs and arms,” said Azaria Dansby, 8, a third-grader at Capitol Hill Montessori, after riding her bike to school. “It’s good exercise, and it’s just fun.”

Owen Stamper, 7, a second-grader at Maury, likes to bike in the rain. “I like when water’s dripping on me,” he said. “It feels really good, and then I feel refreshed.”

Jasper Ruben, 7, a second-grader at School Within a School in Northeast, started riding his bike to school just this year. “It makes me feel happy going down the hill and unhappy going up the hill,” he said as he pulled up to school next to his brother and biking buddy, Gus, 6, who was wearing a Spider-Man helmet.

Fiona Black, 9, a fourth-grader at Capitol Hill Montessori, rides her bike to school, soccer practice and the grocery store, too. “It’s nice, especially if it’s hot, because then you’re going fast and you’re making your own wind so you’re not as hot,” she said.

Big biking ideas

Six years ago, Nathan Havner, who teaches second grade at Maury, started a kids summer camp devoted to teaching bike skills and riding around the city. Kids who attended recent camps had more bike-riding experience than those who came when he started. He figures that in the future, biking will be even more popular.

“It’s a really easy way to get around the city,” he said. But even more than that, “when you’re on your bike, you’re connected to the entire Washington metro area. . . . I can go anywhere. . . . You just have to know how to get there. Once you know how to navigate that, the city just opens up to you.”

A few simple biking rules

Based on tips from the National Center for Safe Routes to School

1. Always wear a helmet.

2. Obey all the laws of the road — including stopping at red lights.

3. Look and listen for traffic.

4. Be predictable. That means make sure that cars, pedestrians and other cyclists know where you are and what you are doing, by saying such things as “Passing on your left.”

5. Watch for cars pulling in and out of driveways.

6. Keep both hands on the handlebars, except when signaling. (To signal that you are turning right, put your right arm straight out. To signal you are going left, put your left arm out. You may need to practice this.)

For more cycling rules for kids, have a parent go to www.walkbiketoschool.org and click on “Keep going.”

— Moira E. McLaughlin