@BluerThanRobinsEggs
Reading has the IDR which is a ring road, in theory, but never finished and then added to, badly. The M4 is the ring road.
Except there is no northern part to the ring. Needs a new bridge, the 3rd bridge around end of A329M over the Thames, up round the back of CPV and across to go over a new bridge to the west of Reading (bypassing Whitchurch toll bridge and Goring/Streatley) to link back to the M4 at J 12 (or between 12 & 13), and with a spur heading north to link up to the M40.
But south Oxfordshire will not have traffic in their county, nor vast acreages of their countryside (quite rightly, it is beautiful) turned over to housing so it won't happen in my lifetime.