It has probably happened to you. You are driving behind another vehicle that seems to be operating rather erratically. The car keeps speeding up, slowing down, or drifting to either side of the travel lane. When you finally are able to get safely get around the car, you cannot help but to glance at the driver to see what caused the trouble, expecting to see him or her engaged in sending or reading a text message. Instead, you watch the driver seeming to talk to him- or herself, gesturing and reacting, despite being alone in the car. Then it dawns on you: the driver is in the midst of a phone …