This would be a silly thing to do in preference to public transport improvements but it would also be silly to maintain the current road scenario. Even with a Bakerloo, Overground extension and DLR, the South Circular will be over congested and a major source of pollution in local centres. It wasn't fit for purpose 30 years ago and isn't likely to become so in the next 30. One way this could work is with a toll road with low emission vehicles exempt.