A senior at St. Charles East High School, Christopher, 18, has autism and an attention deficit/hyperactivity disorder. He was able to pass the written exam for his permit, but struggled behind the wheel in the school's driver's education program. Experts say students with such disorders are challenged in their ability to pay attention, switch focus and remember details. Behind the wheel, they can be easily distracted by billboards and are more prone to road rage, said Gayle Sweeney of Chicago-based Behind the Wheel with ADHD, a group that works with teen drivers. Perhaps most significantly, the group says teens with ADHD are four times as likely to have accidents.