But even if it was, it seems to me that you're assuming a boundary where none exists. There is no fixed point in the road where it's suddenly urban vs suburban vs rural; the most marked points are entry and exit to motorways, but they have lower per-mile risks already.
I'd be the first guy to say that 2000+kg cars ought to be move more safely and predictably; I'm a committed biker, and that would be safer for me too. But in the chaos of UK traffic, I don't really see how it's workable without converting everything - absolutely everything, pretty much overnight - to automated vehicles.
I mean the streets have one lane most of the time, but occasionally two or more lanes between certain traffic lights, junctions are not regular, roadworks at some point in your journey are statistically almost certain, pedestrians are always wandering out into the road, wobbly cyclists, etc. The only way I can see an automated vehicle working in that environment is one that moves unacceptably slowly to mitigate the risk of tort suits against the manufacturer; or an entirely separate road network, strictly for automated vehicles.