“Are we there yet?”

The longest summer drive on average this year will be about 8.5 hours each way, according to a recent survey. If you have children and could only bring one trip accessory – GPS, DVD player, gaming device – what would it be?

Twenty-eight percent of American parents polled said they had to bring a DVD player for the trip to be bearable with children, while the same number would not leave home without a GPS. The random telephone survey by Ipsos Public Affairs, conducted on behalf of used-car dealership chain CarMax Inc., also found that 14 percent of parents said they need extra cup holders when their children are along for the ride, and 8 percent said a car rack is a must-have.

Nearly a quarter of those parents aged 55 and older said they could not survive a long trip without a gaming device, while more than a third between 18 and 34 years old wanted to bring a DVD player.

Only 5 percent of parents surveyed said they would do just fine with old-fashioned car games such as license plate bingo, “I Spy” or “Punch Buggy.''

“The drive to a summer vacation destination can be one of the most memorable and positive experiences for a family,'' said Joe Kunkel, senior vice president of marketing and strategy for CarMax. “With the right car, the right accessories and a good plan, the trip can be enjoyable.”

CarMax offers these tips for making sure your vehicle is ready for the road:

• Check your tires. Inspect the condition of your tires and their tread depth. Be sure to look for any cuts in the sidewalls, and make sure the tire pressure is set to the manufacturer's specifications. Note whether a spare tire is available and in working condition.

• Replace your windshield-wiper blades. You should replace wiper blades twice a year to ensure maximum visibility in all weather conditions.

• Change your oil and filters. Your oil and filter should be replaced every 3,000 to 5,000 miles.

• Pack an emergency supply kit. Put together a care package for your car, including antifreeze, oil, screwdrivers, flares, pliers, jumper cables, flashlight and first aid kit.