Dave, thanks for the great information. I had seen the chart before but didn't really know how to interpret it. Your explanation really helped. Now I know that 12 feet, at least, when TXing is a good distance to keep people out of range. We are talking infrequent PTT in this situation.
Bruce, I run a 50 watt radio in my truck (Yaesu FT-7900R) and will not be running a 110 watt radio in my truck.
I asked the question as a friend of mine has a business band (151.???) radio that he wants to try in his vehicle. He is not operating in the 2M ham band. I just wanted to be able to give him a heads up on the potential for RF exposure.