When I gave my old cell phone to my daughter, I had them shut off the ability to text and go online. I figured that it wasn't something that she was going to start doing.
That isn't to say that people don't get into accidents when they drive and talk on the phone!
Imagine how many people have gotten into car accidents playing with their radio/looking for another station with a better tune.
Sorry for your family's loss. It hits kids real hard at that age. All we can hope for is that other teens will learn from this. Very sad indeed.