most people simply lack the intellect and the concentration to actually operate a motor vehicle
Many people tend to drive distracted. Between looking at phones to catch up on emails, messages, missed calls, and Facebook, or trying to find a good station on the radio, eating chips, drinking cola, lighting a cigarette, or arguing with a passenger. Driving safely only requires that you pay attention to what you are doing. But people nowadays need to be in constant communication with each other, and/or constantly entertained, and driving while doing either (or both) can be dangerous.