What is the best reason to have a cell phone with you when driving?

Maybe it is the natural selection at work.

Stupid people tends to have shorter lives than smart ones.

Many people are overwhelmed by their own confidence that they can handle doing multiple things at once. Some people feel they are too busy during the day, so they squeeze in talking or texting during driving. Others see it as a way to keep their minds occupied if they are bored by driving.