I guess a combination of texting, listening to music and possibly a general lack of sensory perception related to the driving of a car? I don't know. I remember back when I was 18 my mom borrowed my car once and happened to drive past me in the city, doing about 50kph or so
in 1st gear. She just forget to change gears and didn't notice something was wrong, despite the old little engline screaming at 6000rpm. Some people just aren't made for this, it seems.