~ Law enforcement officials say motorcyclists are performing tricks that endanger themselves and drivers around them.

KANSAS CITY, Mo. -- While an unsuspecting driver motors along a two-lane Kansas City road, a man on a motorcycle comes from the opposite direction. The biker is cruising at a high rate of speed when, suddenly, he climbs onto the seat. He straightens his legs, spreads his arms wide and stands triumphantly.

All without slowing down.

It's called "stunting," and it's the latest craze in the motorcycling world.

Although you might not see much of it during wintry weather, law enforcement officials in both Missouri and Kansas say more and more motorcyclists are performing treacherous tricks that endanger themselves and the drivers around them.

"Aggressive motorcycle driving is an issue throughout the metro area," said Capt. Dek Kruger of the Kansas Highway Patrol. "We're seeing 'em popping wheelies on the interstates and performing stunts on the streets.

"It's getting worse. It's getting to the point where a lot of agencies are getting together and asking, 'How can we combat this?'"

And while it's not clear how many deaths and injuries can be attributed to stunting, it's obvious that the activity is dangerous.

According to police reports, a Kansas City motorcyclist was injured in October 2005 while speeding and "driving carelessly." He had been popping a wheelie -- driving with the front tire in the air -- after dark, so oncoming traffic couldn't see his headlight, which was pointing upward.

When a car pulled out in front of him, the motorcycle plowed into the vehicle.

"This is not rare," said Officer Dan Watts, community interaction officer for the Kansas City Police Department's North Patrol Division. "This is happening."

And not only in Kansas City.

In October, a Nebraska man died after he lost control while doing a wheelie, hit two curbs and was thrown.

In Texas, a motorcyclist and his passenger were killed in October when the driver lost control while doing a wheelie. The bike hit a curb, and both victims were sent airborne into an iron fence.

In September, a 3-year-old boy died in Florida after a motorcyclist, trying to do a wheelie, inadvertently landed on the child and dragged him about 15 yards.

The bottom line, law enforcement officials said, is that the stunting craze is contributing to the climbing national figures for motorcycle deaths.

According to the National Highway Traffic Safety Administration, the number of motorcycle fatalities climbed to 4,810 in 2006 -- a 123 percent increase from just 10 years earlier.

In Missouri, 93 motorcyclists died in 2006. In Kansas, there were 64 fatalities. Both were record highs.

So concerned are local law enforcement officials about the increase in motorcycle deaths that they held a summit in June, inviting county prosecutors, bikers and others to discuss enforcement and safety issues. While they addressed concerns about speeding and other related problems -- a Kansas Highway Patrol arrest report from September showed a motorcycle was doing 102 mph in a 35 mph zone, for example -- they spent a lot of time talking about stunting.

One question they discussed: Why is it so popular? Watts attributes part of the phenomenon to the increasing popularity of sport bikes, or motorcycles dubbed "crotch rockets" that are powerful and have tremendous acceleration.

"Is that the only reason?" Watts asked. "No. I'm sure there are other social factors involved, too."

The Internet is awash with footage of motorcyclists stunting, some of it with shots of the Kansas City and St. Louis skylines in the background.

The bikers are popping wheelies at 90 mph or driving on their front tires. They're sitting on their handlebars. They're doing wheelies while passengers behind them hug the bike with their legs and bend backward parallel to the street, just inches off the ground. Sometimes, they're stunting in isolated parking lots and in areas where there is little or no traffic. Other times, they're doing it on busy streets and highways.

Just read this excerpt, written last month on an online message board dedicated to Kansas City motorcyclists: "Should've seen the look on that lady in the passenger seat of the Volvo as I passed on the Benton curve."

Law enforcement officers said the bikers were stunting throughout the area. They've been seen on Interstates 29, 35 and 435, on Missouri 152, and virtually anywhere else they can find long stretches of highway.

"During good weather, we will get daily complaints about erratic motorcycle operations," Kruger said.

Greg Harrison, senior vice president of communications for the American Motorcyclist Association in Ohio, said his organization "does not condone whatsoever" stunting on public streets and highways.

"People who do those activities may call it stunting," Harrison said. "We call it reckless operation."

Harrison said that, while only a small minority of bikers engages in stunting activities, they do "colossal damage" to the rest of the motorcycling community.

"The people that observe them won't remember the number of motorcycles they quietly passed that day," he said. "But they'll certainly remember the ones who came wheelying past or standing on their seat."

In Florida, which had a nation-high 562 biker deaths in 2006, a state legislator is trying to stem the tide by proposing legislation that would force a motorcyclist to serve a mandatory jail term and forfeit his or her motorcycle license for 10 years for simply popping a wheelie.

No comparable laws are on the books in Missouri or Kansas.

Instead, law enforcement officials are looking at citing perpetrators -- if they can catch them -- for careless and imprudent driving or reckless driving.

"Stunting is pretty much the in thing now. It's getting so big," said Brian Smith, founder of the Kansas City-based group Midwest Stunters, which has about 30 members. Many of them get together regularly to ride and perform tricks.

He said stunters were "extremely skilled," and saw no problem with riding in large, open, vacant areas.

But even he said there were limits.

"I absolutely won't do it on the highway," Smith said. "That's too dangerous."