Sir – Prime Minister and Witney MP David Cameron wants the A40 west of Wolvercote roundabout dualled.

But Oxfordshire County Council says the bottleneck is the roundabout, not the eight miles of road west of it.

Enlarging roads increases traffic, so dualling would congest the roundabout more. Railfuture Thames Valley, Bus Users Oxford and Witney Oxford Transport all oppose dualling the A40.

Oxford City Council wants a Northern Gateway business park to create 3,000 jobs at Wolvercote roundabout. This would increase congestion on the roundabout. The PM should oppose the Northern Gateway.

Even if Wolvercote roundabout’s capacity is increased, A40 traffic should be cut. For this to happen, West Oxfordshire must grow less reliant on cars.

In 2011 Network Rail redoubled 20 miles of the Cotswold Line, enabling First Great Western to run more trains. FGW also reintroduced longer trains to increase capacity.

This summer, without subsidy, GoRide increased the bus service to Burford and the Wychwoods and Stagecoach extended its Woodstock-Witney buses to and from Burford.

Network Rail wants to redouble the remaining 10 miles of single track between Oxford and Charlbury. The PM wants this funded as soon as possible. FGW could then increase trains to hourly. Non-car links to stations could then cut road traffic.

Stagecoach’s hourly Burford-Witney-Woodstock buses could meet trains at Hanborough station. And if FGW increased the number of trains calling at Shipton, GoRide’s hourly buses could link them with Milton-under-Wychwood and Burford.

Cheaper than dualling the A40, the PM should then invest in turning the abandoned Chipping Norton Railway into a cycleway to Kingham station.

Hugh Jaeger, Railfuture Thames Valley Branch and chairman, Bus Users UK, Oxford branch