Fatigue is one of the leading causes of crashes. Tiredness can slow your thinking, lengthen your reaction time and cause you to scan inaccurately. To stay alert behind the wheel (especially on long trips), make sure you are well rested before you start your trip. To keep alert during the trip, take several breaks along the way. Walk around and get some exercise. Eat moderately but avoid heavy meals because they may make you feel sleepy. Keep a window open for fresh air and sing or talk to keep yourself paying attention. However, if you find yourself getting sleepy, pull over to a rest stop and take a nap. Be sure to lock your doors.