Which factor increases the risk while driving a car because it interferes with attention?

Here are some following risk factors of interference of the driver attention:
 
1.Your friends
2.Your phone
3.The radio
4.Illness
5.Sleepiness
6.Television
7.Emotions(Anger,Sad,Scared)
 
Reason why:

1.It can be your friends that are in the car alongside of you, they can be distracting you while your driving by talking pointing out things making you focus on things you shouldn't be.

2.A lot of people get into accidents while texting and driving, they focus their attention on their phone instead of the road.

3.Some times the radio can be a little distracting too. Your favorite song might come on and you would want to dance or sing (some people like to close their eyes and sing), you might start swerving and crash.

4. Your sick and not feeling well, your probably not feeling up to the task feeling drained.

5. Your most likely to fall asleep behind the wheel and crash.

6. A lot of cars have mini t.v screens to watch movies, you might get distracted while trying to drive and watch your new t.v episode or movie and crash.