You can also read the mind of most drivers, if you are a bit skilled in body language.
One of the things I notice is that people talking on mobile phones while driving go into a sort of "autopilot", like they are sleepwalking. They stay in their lane and cue on certain things, but they aren't really paying attention.
If I am driving in the right lane I notice people on phones like to ride in my blind spot behind me to my left, as if they are flying formation with me, not really watching the road but watching me out the corner of their eye and basically just following my moves.
If I brake suddenly to let them pass (because I HATE people driving in my blind spot, especially with headlights shining in my sideview mirror), they will blow past me before reacting, but they will also brake, for no reason other than they saw me do it first.
I'm not going to get into a discussion about cell phone use, but I find this aspect of human behavior to be very interesting, to see how people put one task on autopilot while they focus on another, and how their "autopilot" operates off of certain cues. This has implications way beyond driving.