I'd propose online widening with property demolition in order to bring the road up to modern expressway standard, using collector/distributor road for Oxford traffic6637 wrote: Way I see it, the eastern route around Oxford makes more sense as:
1) The existing A34 past Oxford doesn't have enough capacity, and the section through Botley is restricted to only 50 mph. There's no obvious way to bypass that section.
It very much depends what you mean by through traffic - if you mean Birmingham to Southampton, then you're wrong. Also, they're leaning towards Option B, which would mean that the eastern route around Oxford wouldn't have the same benefits as if they were building Option C2) For through traffic, a route that goes west of Oxford would be significantly longer than one east of Oxford.
Option B appears to cross near Bicester, and S3 shows some multiplexing with the M40 S2 and S3 then join the existing line north of Abingdon, whereas to be more than a glorified Oxford distributor and to maximise the attractiveness of the route they should probably join at Didcot.3) If you use the route east of Oxford, the new road will probably have a fully-freeflow junction with the M40. I expect the new road would multiplex with the M40 for a few miles just north of J8.
S1 seems the best route to me additionally as it avoids the creation of another transport corridor and could improve considerably on what's there already.
The Western route better serves western Oxford as well as Bicester and the M40....4) The eastern route better serves eastern Oxford, as well as Aylesbury and the A41.
Also, improvements to the western side could incorporate a better connection to the Whitney bypass and improved M40 junction to try and divert A40 through traffic away from Oxford itself.