RFID technology. Most cars already have that installed for pushbutton starting. They just need a couple more RFID antennas inside, and the small computer control with firmware that triangulates where the phone is. Driver's seat and the car is rolling - DISABLED. Except for 911.
RFID doesn't really work like that. What gets closest to what you are describing is bluetooth beacon technology, and then you'd have to have your car rigged in such a way that you'd need beacons all around you. It wouldn't be practical, would be inaccurate and expensive. On top of that there would be no way of knowing that the phone that is charging in the center of your dashboard is operated by the person that is driving the car or sitting in the passenger's seat. If you'd like to do this you could use technology thats been around for a while and use image recognition to see if the person operating the phone is in the drivers seat or not. Even better would be to not use the phone's camera but have a camera inside the car that detects this as to not drain your phones battery life and have a better angle.
My personal opinion: you don't have to fear that the government will force you into using a stricter form of this. Its already illegal to use your phone while driving, they can maybe mandate you have it turned on when you are the driver. Just like many countries around the world mandate that you use a bluetooth headset while calling and driving. But they can't force you to not break the law.
