There are many ways autism may impact driving skills. For the purposes of this article, let's talk about a subgroup of those on the spectrum who have intellectual knowledge that is adequate to drive but who avoid or feel overwhelmed while driving.
1. Executive Function
The center and front part of the brain is in charge of executive function. This ability includes many things such as quick thinking and decision making, attention to detail, shifting attention to what is most important in an environment that keeps changing, monitoring speed (keeping pace), and showing flexibility when unexpected things happen.
For some on the spectrum, executive function is too impaired for them to safely drive. That is, they may struggle with reaction time and attention to details so much that they are unable to attend to the changing environment in a way that is safe.
For others, they show adequate attention and speed for most driving environments, but struggle with anxiety in traffic. They may say, "I love to drive... when no one else is on the road." The driving itself may feel soothing, but adjusting to the surrounding cars, street lights, road signs, and other details of the road is completely overwhelming. Picture a conveyor belt of information coming at you so quickly that you just can't keep up with it all!
Most often, driving is boring and mundane. We may even lose track of time and wonder how we got to our destination so quickly. Our mind may have been wandering to other topics. But when unexpected things do happen on the road, they are often very important: our usual exit is closed, a car cuts us off, a tire is in the road, a child runs out to get their ball. And this doesn't even take into account the weather! The driver needs to have enough flexibility to know what to do when it is snowing but the speed limit says "55." I had one patient who followed that "rule" even though he should have adjusted his speed because of the weather. Luckily he survived, but his car didn't.
New drivers on the spectrum may eventually be successful with driving safety in many environments, but may take longer to achieve their license. These individuals may also choose to avoid certain driving conditions because of the challenges above.