While it very well might be the case that Google Glass is unsafe for use while driving, that doesn't mean any wearable tech is. Glass can display anything like a video or a game or your email which is not a great idea. It could also display navigation apps, monitor your alertness and even detect and warn you of potential hazards before you spot them, which are great uses.
The problem is PC Plod cannot tell which you are using it for and that is a big problem. Wearable tech should maybe have to support a "I'm driving" mode to be allowed. Glass is really a prototype, there are many details to be worked out for real life use.