Absolutlely. It's no different than talking to anyone else who is in the car for me. BUT, it's totally an individual thing, everyone is wired differently in their brains. If I'm talking on the phone and something happens on the highway, the person on the other end will get dead silence and I'll tune out what they're saying for minutes at a time. When I finally get back to them, they're all concerned because I haven't said anything for like two minutes, and I've missed everything they've said. Some other person would be like, "oh, I'm about to crash into someone ... do you think I should hit the brakes? ... oops, too late."
Like I said, it's totally dependent on the individual. When I used to watch TV with one of my ex-girlfriends, she'd be like: "what do you think of this commercial?", me: "I've never seen it before", her: "what do you mean, it's already been on 3 times during this program"; me: "do you seriously listen to the commercials while watching TV?" After having the same conversation numerous times over many months, I just realized our brains were wired totally differently. She just couldn't avoid listening to the commercials, and I just automatically tune them out.
Different people have different personal risks for driving (just like any other task). I expend a lot of energy on attentiveness while driving, but that usually means I'm exhausted after driving 2-3 hours. Others don't put that much energy into it (which IMHO is bad), but while I might be the better driver for those first few hours, get to hour 4, 5, 6 of a long drive and they're a better driver than me. Our laws and how they interact with the auto insurance system force us to treat everyone the same when we probably shouldn't.