I would prefer it if these AI controlled cars were restricted to special roads or lanes. Otherwise they are manually operated. Mixing AI and manual cars on country lanes or in busy towns and cities is going to be dangerous, no matter how good the AI is. At best, city centres modified to help AI vehicles with a 15 or 20mph speed limit might work, with the emphasis on discouraging human driven vehicles from entering that area at all. Minus the AI vehicles, this is how many city centres are moving now anyway with high parking charges, limited parking, congestion charge areas, shared vehicle/pedestrian areas, roads closed to traffic and permanently pedestrianised or at least during working/shopping hours.
We currently have rail based trams "on" the roads in some cities, special guided bus lanes in others, so there are models for some limited and partially segregated traffic already. Adapting this to motorways should be do-able.