Before I would install a VHF/UHF transciever in a Prius, I would contact Toyota directly, via a Factory Rep. I remember reading somewhere (maybe the manual) that the Synergy Drive System is susceptable to RF interference.
N6OYU,
It will probably work ok as long as you're not using a lot of power. Most of the new cars especially the Japanese ones go thru rigorous RF testing and I'll bet that you can get the test data. Not like the days of old when I had a 1982 AMC Eagle that would change speed every time I keyed the mic on 2m while on cruise control.
73, Ralph
WA1TSL.
I've used a UHF/VHF HT with a cigarete lighter adapter and a window mount antenna many times with no problems. The HT is only puting out 5 watts though.