One handed typing is useful everywhere, not just while driving. We all are guilty of using our phones while driving. No matter what anyone says it is still not a good idea. I am guilty of it myself. I am not as crazy about that as one person I know, who sends emails to our organization telling people when they get an email on their phone they should pull over and read it and then respond. I'm driving along, I get an email and I read it about 2 words at a time and if it is urgent I call the sender using handsfree bluetooth goodness, if it's not urgent I just wait. It's not like anyone is going to get upset if you tell them "I was driving so I waited till I got to the office to respond". Maybe you're not driving erratically but if someone ELSE is texting or surfing the web and swerves right into you and you don't see it coming and you get shoved into a phone pole at 60mph and leave behind a family, was answering an email or text really worth it?
but anyway, good information about keyboards...