First the problem was driving while texting, then that was banned in many places.

Now walking while texting is the latest scourge.

But some experts say that one of the most dangerous distractions on the road today is having an unrestrained dog in the car with you.

Whether its curled up on a lap, hanging out the window or resting its paws on the steering wheel — your best friend can be deadly. Tens of thousands of car accidents are believed caused every year by unrestrained pets, though no one has solid numbers.

"An unrestrained pet can be hugely distracting — if he is seeking your attention, putting his face right in front of yours, starts chewing up the upholstery or is vomiting because he is car sick," said Katherine Miller, director of applied science and research for the American Society for the Prevention of Cruelty to Animals.

The issue is drawing attention in some statehouses. Hawaii is the only state that specifically forbids drivers from operating a vehicle with a pet on their lap. But Oregon lawmakers are considering fining drivers who hold their pets behind the wheel. And some cities are taking action, too.

In 2009, 5,474 people were killed and 448,000 were injured in crashes caused by distracted drivers in the United States, according to the National Highway Traffic Safety Administration.

Cell phones were the top distraction — the cause of 18 percent of the fatalities and 5 percent of the injury crashes. The agency does not track accidents caused by pets, but said they are counted among other distractions such as disruptive passengers, misbehaving children or drivers who attempt to put on makeup or read.

Author Stephen King suffered several broken bones and a collapsed lung in 1999 when he was hit by a driver who claimed he was distracted by his dog.

In a crash, an unrestrained pet can turn into a deadly projectile or get crushed by a driver or passenger who is thrown forward by the collision.

Good pet owners will use a harness or carrier and secure their pets in the middle of the back seat, Miller said. That keeps dogs from getting hurt or bouncing around and hurting others.

"A pet that weighs 50 pounds, in a 35-mph collision, is projected forward like a cannonball with 1,500 pounds of force, and that can cause critical injuries to the folks in the front seat," Miller said.

Restraining a pet also keeps the animal from running off after a crash and possibly getting hit or causing another crash, or from getting in the way of first responders, she said.

Susan Footh, 37, of Whitewood, S.D., said her 12-pound Maltese named Mozart could have been killed twice if he hadn't been wearing a harness.

Footh was on her way to a Christmas gathering when her car veered out of control on ice. She smashed into a highway barrier three times before the vehicle stopped. Presents flew through the car, her coffee splattered all over the back window. But Mozart stayed put.

Then, a few weeks ago, another driver clipped her bumper while trying to pass, sending her first into a spin and then into a ditch.

"Mozart was shaking," Footh said. "I'm sure he was saying, 'Not again.'" She was able to put the car into four-wheel-drive and climb out of the ditch.

In Oregon, lawmakers will vote in the next few months on a bill that proposes a $90 fine for people who drive with an animal on their lap.

A similar law made it to the governor's desk in California in 2008, but then-Gov. Arnold Schwarzenegger refused to sign it, saying it was not a high priority.

Bill Pace, the former assemblyman from Visalia who introduced the failed bill, said he frequently sees drivers with "animals up in their face, in their lap and on the steering wheel. ... This is not a rare occurrence."

Some cities have passed laws of their own. In Troy, Mich., a law took effect Jan. 1 that makes it illegal to drive with a pet in your lap.

But Jonathan Adkins, communications director for the Governors Highway Safety Association, doubts that many states will single out pets.

Elected officials "can't have a law to outlaw every bad driver behavior," he said. "You go after the big ones."

But Adkins said the problem is underreported because the only way to know that a pet was at fault is if the driver says so.

Education about pet restraints will have to come from pet owners, vets, animal-welfare agencies and insurance companies, he added. And that could take years, just as it took a long time to get people to wear seat belts.

The Associated Press contributed to this report.