On the surface, Road SMS for Samsung Android Phones and Type n Walk for the iOS are really cool apps. Both are designed to let the user type while walking and driving, by using the built-in camera to turn the phone into a see-through keyboard. The major difference is that Road SMS is simply an SMS messaging app, while Type n Walk works with nearly any iOS keyboard.
Nevertheless, you might want to avoid both of them. Both apps may make typing on your touchscreen less obtrusive, but they also encourage using the phone in situations where it should be kept in your pocket. Trying to compose a message while driving—even if you can still see what's up ahead—is really very dangerous. That's something we learned the hard way. And even texting-while-walking creates its own set of problems, such as a diminished awareness that leaves you more vulnerable to snatchers.
If your safety doesn't sound valuable enough, just think about your gadget. They don't hold up very well in a crash, and practically disappear once stolen.