Your mechanic has given your car the once-over, so you’re ready for your long journey, right? Wrong.

“Get some sleep — that’s the important thing,” says James Joseph, author of 110 Car and Driving Emergencies and How to Survive Them (The Lyons Press, $13). Falling asleep at the wheel is one of the leading causes of fatal single-car accidents, according to the National Highway Traffic Safety Administration. If last-minute preparations have worn you out, don’t be too ambitious on your first day. When charting your course, plan to be on the road no more than eight hours a day, and factor in 10-minute breaks every two hours.

Bring an emergency supply of any medications you need — along with your spare pair of eyeglasses. Also stock the car with a gallon of water, a flashlight with extra batteries, Fix-A-Flat, and a pillow. “It can make all the difference to a good night’s sleep,” says Megan Edwards, the founder and president of the website RoadTrip America (www.roadtripamerica.com).