It's sad to say this but common sense does not prevail, and although we cannot legislate against all stupidity, we can legislate against costly and dangerous stupidity. That is why we need laws, because common sense as it turns out, is not all that common.
A July 2009 Virginia Tech study found that drivers who send text messages while driving were 23 times more likely to cause crashes than if they were not distracted. A 2003 University of Utah report's results indicate that "distracted drivers" are more impaired than drunk drivers.
The Harvard Center of Risk Analysis estimated cell phone use attributed to crashes costs the U.S. $43 billion a year and causes about 2,600 deaths annually.
The time has come to protect people from their own irresponsible behavior.