I suspect the main "roadblocks" are about the environment for the SDC. All traffic signs and signals need to be machine readable at a distance. That is, a traf

I suspect the main "roadblocks" are about the environment for the SDC. All traffic signs and signals need to be machine readable at a distance. That is, a traffic light might beam out "I am light 'SFTL783', will be green for 8 more seconds". The location and other data for SFTL783 is in a preloaded database. Same for speed limits and other signage. An updated 3d map of all roads would also help a lot. As would car-to-car communication systems.