writes "Talking on your cellphone while driving isn't a crime in most states, but it should be. Studies have shown that people who drive and talk are many times more likely to have an accident. A new company is releasing a device to automatically detect drivers talking on their cell phones. Instead of police officers needing to observe a cellphone in use, the system automatically detects a cell phone call and records which car was making the call."
The article is fairly light on details, but it would be interesting to see how the system differentiates from a driver talking on a cell phone versus a mere passenger.