They ride like the wind, sometimes leaving puzzled pedestrians and furious motorists in their wake. They have their own vocabulary, and you'll need my glossary below.

Where the youth culture and the bike culture intersect, you find stunts — often done in traffic — that you didn't know you could do with a bike, and in some cases shouldn't do. The kid riders are a subculture of a subculture, and they are bringing what some find to be an unwelcome change to our streets. They are almost always male but represent all races, like a U.N. balanced on two wheels.

Motorists on Broad Street or Market Street in Center City, and other locations, periodically encounter swarms of bike-riding kids, usually teenagers, taking over an entire street from curb to curb. Many of them are riding on a rear wheel, forcing cars to stop or to carefully steer around them.

"Someone is going to be badly hurt," an older Center City resident who has seen the swarm tells me. "Some motorist will start shooting," she says. On social media, one man complains that the kids "think they are having fun, but this is lawlessness."

Seizing a street is often part of a planned group ride, called a rideout. The most famous one was in April, when more than 300 kids rode their bicycles onto the Vine Street Expressway. It was amazing, dangerous, and frightening.

That rideout was to celebrate Corey Murray's 16th birthday, and state police — because 676 is an interstate highway — nabbed him. Perhaps Philadelphia's best-known rider, Murray is known among bicyclists as OneWay Corey, the "one way" coming from "one way up," as in a wheelie. To him, riding with friends is fun and freedom. The South Philadelphia High School junior got six months' probation.

Murray says giving him "credit" for the infamous highway ride is misplaced.

"I didn't lead it to the highway," he says, adding that he doesn't know who did.

Michael McGettigan, who owns Trophy Bikes in Northern Liberties, finds that believable. "Suddenly you're in a big group, just like when small fish gather together to appear to be one big fish to predators," he says. "There is no leader."

Taking over the highway was unusual. Kids usually do their tricks in the street, in traffic. Cops know about the renegade riding but can't do much about it unless they know it's about to happen. They find out in three ways, a police spokesman, Capt. Sekou Kinebrew, tells me.

"If it's planned or organized, there is some evidence of it on social-media platforms," he says, and cops monitor YouTube, Facebook, Twitter, and Instagram.

Officers on patrol may see it, and civilians may call 911.

Mostly the bicyclists ignore traffic laws, copping the attitude that cars have to look out for them. Some day, that will lead to trouble.

Thanks to social media, rideouts are increasing, and they have taken a dangerous turn with a stunt called swerving, in which bicyclists cut into the path of a motor vehicle and then quickly swerve away. Or try to.

Murray admits to swerving until a couple of years ago, when he got clipped by an SUV, sending him over his handlebars, injuring his back.

"That's when I stopped swerving cars and stuff," he says. "It's dangerous, and it's just stupid."

The bicyclists have many less-perilous stunts. These include:

  • The wheelie: The rider pulls his front handlebar up and rides on the back wheel.

  • The nose wheelie: The rider is on the front wheel.

  • The Superman: The rider is sliding back, resting his chest on the seat with legs extended, mimicking the comic-book hero in flight.

  • Surfing: The rider stands on the seat as if it's a surfboard.

  • The bunny hop: Both wheels come off the ground.

  • Draggin': The rider leans all the way back, dragging his hand on the ground behind him.

Murray invents a lot of his tricks, but "sometimes you see them on social media and you do it," he says. There are dozens of tricks. Here are 10. 

Some are dangerous, especially when done in traffic, and they require truly amazing dexterity and reflexes. That's one reason, Murray says, his bike-riding friends stay away from drugs. "Bikes are our drug," he tells me.

Kids like Murray are revolutionizing how young people use bicycles, have fun, and feel freedom. They're not going away any time soon. We wheelie ought to be ready.