There are three proposals for reorganising local government around Oxfordshire and a consultation on them is running. Here I just look at some of the transport and planning implications.
The Oxford Clarion has an explanation, but the options are: 1) "One Oxfordshire", retaining the existing Oxfordshire boundaries as a unitary authority and merging the functions of the district and city council into that; 2) "Two Councils", dividing what is now Oxfordshire plus West Berkshire into Oxford & Shires and Ridgeway; and 3) "Three Councils", with a Greater Oxford and North Oxfordshire and Ridgeway councils taking the rest.
One Oxfordshire
The One Oxfordshire proposal is the easiest to understand — no map is necessary as this would just keep the existing boundaries of Oxfordshire. It would fix the obvious problems with planning - housing sites around Oxford being in district councils while the employment and services for the people living in that housing are in the City. And it would end the disconnect between planning for developments and for transport.
Two Councils
The Two Councils proposal is I think the worst. It pretty much completely fails to fix the planning problems around Oxford — Oxford would be part of an "Oxford & Shires" Council, but almost all of its surrounds would be part of a Ridgeway Council, so the latter would be in charge of building housing to serve the former. This proposal also makes transport significantly worse, with two highways authorities instead of one (as now) having to coordinate to build cycle routes into Oxford (the Greenways), manage bus routes into Oxford, and plan for commuter traffic generated by employment in Oxford.
The Ridgeway is great for hiking, but not otherwise a transport nexus of any kind: half the people in a Ridgeway council would look to Oxford for employment, services, etc. and the other half would look to Newbury and Reading. As you can see from this map of commuter flows, Oxfordshire is a natural transport unit, with the exception only of Henley. Adding West Berkshire onto it (or part of it) makes no sense at all. (But if Banbury is part of Oxfordshire then perhaps Brackley should be too.)
Three Councils
The Greater Oxford proposal would fix some of the planning problems around Oxford, but doesn't go far enough. It would exclude developments that are clearly happening to serve Oxford, such as Salt Cross, and leaves Abingdon disconnected from its surrounds. And for a Greater Oxford to work from a transport perspective, it would need to include at least the extent of the Greenways (the planned cycle routes into Oxford) and Park and Ride locations at Eynsham (the Central Oxfordshire Travel Plan covers Eynsham).
This proposal also creates two other councils which seem very awkward from a transport perspective. The problems with a Ridgeway council were described above, and if you look at the main roads in the proposed Northern Oxfordshire council, they all run to Oxford. And of course this would mean splitting up everything else (adult social care, child services), which seems contrary to the goals of the reorganisation.
Summary
For transport at least, there needs to be a balance between the interests and mobility requirements of residents of Oxford and those living outside it but working there or using its services. At the moment these all fall under the one highways authority, and dividing them between two or three seems like madness.