[ktRolster]

Let's assume that we have all the algorithms discovered, the prototype works excellently. For example, all the problems with snow and weather have been solved, as well as the logistical problem of making an extremely accurate 3D map of the world. Google has their prototype working everywhere: it's ready to be implemented as production quality (it has to be better than Android).

Writing high quality, reliable code (for example, in airplane control software), including testing etc, tends to take 5-8 years. So from a project management perspective, that's the reasonable estimate.