Study finds daydreaming the top cause of distracted driving accidents.

http://www.foxnews.com/leisure/2013/04/05/study-finds-daydreaming-top-cause-distracted-driving-accidents/

Update:

Now that I have some time, I'd like to comment upon this.  As far as daydreaming goes, as long as you don't take your eyes off the road, you can react to what happens in front of you.  You may not be aware enough of the other sides of you, but at least the stuff in front you can see.  On the other hand, if you text while driving, you can't see what's ahead of you.  You can run right into it.  There was a fatal accident a number of years ago here in Houston when somebody was reading a newspaper while driving on a freeway at highway speeds. He ran into somebody and it killed him.  Therefore, I wouldn't agree with this finding.