[Publius6961]

The results indicate there may be a "distracted-driver personality" type behind the wheel.

Golly...
All this time we've been calling them idiots.

People who don't know their limitations.
Indeed, who don't have the mental horsepower to know that limitations exist.

[brianl703]

I see this all the time: The people who want to go faster than everyone else but who have poor depth perception or something, so their attempt at weaving through traffic consists of:

Getting right up on someone's bumper before realizing that the vehicle in front of them is going SLOWER than they are.

Then they hit the brakes, put on the turn signal, and (probably) depending on how close they've come to sideswiping someone lately, either start changing lanes without looking, almost sideswiping someone, OR they take 20 seconds to change lanes even though the lane they want into is empty.

It's almost like the concept of the side-view mirror is alien to them.

One of these idiots I saw a couple of weeks ago managed to get stuck behind a tractor-trailer with another tractor-trailer on his left (he was in the far right lane).

More often than not it's the people who have "commanding views of the road ahead" who do this. As though being higher up and therefore able to see further will help what is clearly a problem between the seat and steering wheel...