Many people keep their mobile phone ON when they drive, and pick-up the phone when it rings. This endangers many lives.
"NoPhoneInCar" automatically rejects incoming calls when you move : Just set the threshold speed and switch to "Automatic" mode.
The "Phone always ON" mode leaves the phone in normal mode whatever the speed is (intended for passengers).
The "Phone always OFF" mode refuses incoming calls mode whatever the speed is.