David, good thought provoking article that brings in the world view for self-driving cars. I think like with everything, there will need to be global standards that are agreed or some type of convertor. Think about power globally. Now, most international travelers carry a power converter in their suitcase or the hotel will offer one. Or think about wireless technology where TDMA, CDMA or GSM were fighting for global acceptance. We now roam freely.
A bigger issue will be to agree on security up front on both philosophies. If security is an afterthought, a bolt-on, then agreeing on a global standard will become even more important. If either Europe of America consider security issues while they are developing and creating technologies for self-driving cars, then there is a shared risk that can be considered when developing standards.