I've often wondered why we haven't been spending some effort developing optimized test areas which integrate helpful elements for self driving cars into the ro

I've often wondered why we haven't been spending some effort developing optimized test areas which integrate helpful elements for self driving cars into the roads. Obviously, we wouldn't want a car that couldn't go everywhere, but it seems like at a national level, we could implement something into the highway system that would make it easy for interstate self driving vehicles.