I ride only in the countryside but having commuted daily to work in SF, NY and London, I can see this might work well.
The question is whether the symbol is really visible in amongst all the other lights in an urban environment.
I spent six months working with a driving psychologist, the bus company and a lot of other cyclists – one stat stood out, the fact that 79 per cent of cyclists hit are travelling straight ahead and the vehicle turns into them.”
http://road.cc/content/news/111141-bransons-back-blaze-laser-projection-bike-safety-light