There are many types of distractions that can result into any damage.
Gadgets: I think this is the most common distraction while driving. when people are using gadgets in the car like Cell phones, mp3 players or very busy searching something on GPS, their mind gets distracted from the road and get distracted. This is very dangerous. There is fine as well on using gadgets while driving, but still everyone uses the phone no matter what.
Anxiety: sometimes prior whole driving is in different moods or too tired. This type of anxiety pops up lot of thoughts in your mind which ultimately distract you from driving.
Other road accidents: when there is accident on a road, people generally divert them to look what happened exactly and ultimately look control on the car.
Overtaking: i have seen many people overtaking other cars just for fun. Now this creates lot of trouble on the complete road and every other driving on the road gets affected by it.
Other passengers: now if you have passengers in your car like your wife or your kids, sometimes people get distracted from the road and their mind runs in playing with their kid in the car, which is wrong. Driving is never s perfect time to pay with your kids in your car. There have been lots of accidents because the driver was busy passing with his kid and suddenly banged another car. The accident becomes more crucial in that case because even the small kid gets injured badly sometimes.
Pedestrians: it may sound funny, but sometimes if a guy is driving and he see a beautiful women passing by, he get lost in her and don't really handle the steering properly. I mean it’s wrong. Anything can happen not only to you but to the other pedestrians as well.