Distractions while driving have severe consequences. Studies at the National Highway Traffic Safety Administration indicate that reaching for an object increased the risk of a crash or near-crash by 9 times; looking for some address or other object outside the car by 3.7 times; reading by 3 times; applying makeup by 3 times; and dialing a hand-held device (typically a cell phone) by almost 3 times. Actually talking or listening on a hand-held device was only 1.3 times ["only" being relative].
 
In the NHTSA and the Virginia Tech Transportation Institute study released in 2006, nearly 80 percent of crashes and 65 percent of near-crashes involved some form of driver inattention within three seconds before the event. Primary causes of driver inattention are distracting activities, such as cell phone use and drowsiness.
 

Source: National Highway Traffic Safety Administration website

 
Since that study was released, the incidents of driving while text messaging on cell phones, especially among teenagers, has risen dramatically. The combination of being an inexperienced driver and succumbing to distractions is now a leading killer of teenagers.
 
In the study, cell phone usage was the most common distraction, accounting for 7.2% of crashes. However, the incredible corresponding fact is that all those other distractions accounted for almost 93% of distraction-related crashes.
 
I bring all this up for several reasons:

1. Removing distractions while driving can have a dramatic effect reducing crashes and near-crashes.
2. Certain uses, cell phone use and now text messaging, are growing distractions as a percentage of the whole and bares continued review and consideration.
3. [I hesitate mentioning this one but it's important] Banning hand-held cell phones in school zones barely addresses the real problems, leaving well over 93% unaddressed, because dialing a phone is more than twice as distracting as using it and we know text messaging is even worse, but those can't effectively be banned.
4. Passing laws that have only a minor affect on the range of distractions really are no more than "feel good" laws and can leave other drivers and pedestrians with an unrealistic assessment of the true risks. Good intentions can be harmful.

The best way to address inattention while driving is not more laws, but education. For me, in this research process, I've become much more conscious of the types of distractions that surrounds us constantly as we drive. When driving, my most common words to my son, when he tries to get my attention (catch that?), have become, "Just a moment, son, I'm driving." It makes sitting at a red light much more productive.
 
If searching for a street sign increases your chances of a crash 370%, imagine how much the whole list of distractions could contribute to your chances of a crash. Then imagine how reducing those distractions, not letting them intervene, postponing some action, significantly increases your safety and life expectancy, and your family's.
 

 
Caution: The study is voluminous and bares careful review. Seemingly obvious points often have complex undertones and consequences. A casual scan can leave false conclusions so I advise not taking a few points out of context but studying the list of materials for a fair analysis.