The fascinating thing about SD cars is that actually, they don't need to pre-map routes in excruciating detail. They carry enough sensing equipment (the primary

The fascinating thing about SD cars is that actually, they don't need to pre-map routes in excruciating detail. They carry enough sensing equipment (the primary being LIDARs) to build high detail maps on the fly, along with recording the location of other road users. Low-detail, pre-mapped, road maps are mainly used for routefinding rather than second-to-second navigation.