According to a study written about in The Sunday Times, driving more than 2 hours per day negatively affects the brain by way of reduction of intelligence.
Medical epidemiologist, Kishan Bakrania, quoted:
“We know that regularly driving for more than two to three hours a day is bad for your heart. This research suggests it is bad for your brain, too, perhaps because your mind is less active in those hours. Cognitive decline is measurable over five years because it can happen fast in middle-aged and older people. This is associated with lifestyle factors such as smoking and bad diet — and now with time spent driving."