CLEVELAND - To a dog that loves to stick its head out a car window to feel the wind, insurance is not a concern.

An auto insurance company is now offering their owners a benefit for pets.

Progressive Corp., based in suburban Mayfield, Ohio, is providing collision coverage for customers' dogs or cats at no additional premium cost. It will pay up to $500 if a customer's dog or cat is hurt or dies in a car accident.

"It's an unusual and interesting benefit," said Jean Salvatore, a senior vice president for the Insurance Information Institute in New York. She was not aware of any other company offering a collision benefit for pets.

"Auto insurance is a very competitive market, and companies are always looking for ways to differentiate themselves. If this becomes popular, I'm sure others may look into it as well," Salvatore said.

There are more than 150 million pets in the United States, and Americans spend more than $40 billion on their pets annually, according to a recent Insurance Information Institute study.

The Progressive benefit has been in place since Sept. 6, and it's too soon to determine whether the company's undetermined cost of offering it will be offset by better sales, said Progressive spokeswoman Leah Knapp.

Auto insurance generally provides property, liability and medical coverage.

Typically, an insured person's collision coverage pays for the damage to the insured's vehicle in a collision or other kind of accident, such as when a driver loses control and a car overturns. But usually there is no payment for pets that might be in the car.

Liability coverage would kick in for any pets hurt in a car other than the insured's.

The new Progressive benefit is not pet insurance, which some people obtain to help them pay veterinarian costs.

A Progressive strategist said the company saw a pets benefit as an auto insurance market opportunity.

"We found no coverage that was even similar to it," said Geoff Souser, Progressive product manager for auto insurance. "We have pets, too, and we know how important they are to our families. We are always looking for new and different ways of delivering value to our customers, and this seemed like a logical extension."

Progressive is the third-biggest auto insurer, ranking behind State Farm and Allstate and slightly ahead on National Indemnity (Berkshire Hathaway), which includes GEICO.

Progressive's pet benefit is available in 46 states and the District of Columbia. It's not yet available in North Carolina, New Hampshire, New York and Virginia, but the company hopes to offer it in those states soon.