Americans can't bear to be apart from their pets, which often travel alongside their masters in the car and sleep on the foot of the bed in pet-friendly hotels.

Consider this stat: 29.1 million Americans say they have traveled with a pet on a trip of 50 miles or more in the past three years, according to the Travel Industry Association of America. And most of those dog and cat lovers -- 76 percent -- used a car as their primary mode of transporting their pets.

Like babies in cars, dogs in cars are here to stay. But traveling safely with a dog or cat is not as easy as merely loading the animal in the car and hitting the gas.

Here are some safety tips to ensure that your dog or cat has a safe trip on the road, according to Andrea Arden, who has written five books on dogs and was the behavior columnist for Dog Fancy magazine. She has teamed up with Progressive Group of Insurance Companies, which offers pet injury coverage.

Restrain your pet in a crate or a harness to keep him safe and so he won't be a distraction to the driver.

Resist the temptation to let a dog stick his head out the window, even though he loves the feeling of blowing air. A dog can be injured by debris flying into his eyes.

Never leave your pet unsupervised in the car.

Try not to feed a pet before a trip because some tend to get sick on the road.

Ms. Arden also offers tips on getting your pet comfortable about the car before the trip -- especially if the animal is loathe to travel because he associates it with a trip to the vet.

Take him for fun short car rides to a park or a friend's house.

If your pet's anxiety persists, consider over-the-counter products that can help reduce stress and anxiety.

If you plan to keep your pet in a travel crate inside the car, familiarize him with it beforehand. Let him rest inside it around the house.

Make sure your pet wears up-to-date ID tags in case he or she gets lost in transit.

Bring a doggie bag, filled with clean-up supplies, a bed, portable watering/feeding bowls, food and water, a pet first-aid kit -- and lots of toys to distract him while you rack up the miles.