> is highly impractical and dangerous. And illegal in the State of California

It’s technically possible, and not that hard, to implement a voice-based interface for that, using e.g. Bluetooth + car stereo.

You setup your preferences while the vehicle is not moving to filter the offers you want to receive, by criteria like price/km, geography, min. total price. Then the software uses voice interface to read you the incoming offers, and listens to your “accept/decline” voice commands.