Sir – Prime Minister and Witney MP David Cameron claims A40 congestion is “a foot on the windpipe” of West Oxfordshire’s economy.

Actually, the district is thriving compared with much of Britain.

The foot on everyone’s windpipe is too much motoring.

Mr Cameron missed county council leader Ian Hudspeth’s excellent Connecting Oxfordshire forums this summer.

The loudest and longest applause at any of these was when 100 Witney constituents welcomed a Carterton-Witney-Oxford tramway proposal.

None of them even mentioned dualling the A40, which Mr Cameron had proposed a month before.

Improving road junctions sometimes eases bottlenecks but major road enlargement encourages more traffic.

Dualling seven miles of A40 from Witney to Wolvercote would take years, cost many millions of pounds and increase congestion and vehicle exhaust emissions at both ends.

Next year Chiltern Railways will open Oxford Parkway station at Water Eaton.

Its trains to Bicester, High Wycombe and London Marylebone will be low-carbon, but hundreds more car journeys from West Oxfordshire to Oxford Parkway will worsen congestion and emissions at already overloaded road junctions between Wolvercote and Kidlington.

Mr Cameron also wants more of the Cotswold Line dualled in order to increase the train service.

We do too, as regular buses could then be run to connect with trains to and from Oxford, London and Worcester at Hanborough, Charlbury and Kingham stations.

Rather than dualling the A40, we suggest a high occupancy vehicle lane, restricted to cars with three or more occupants plus buses and taxis.

It would be signal-controlled, eastbound in morning peaks and westbound in evening peaks. It would cost less and, unlike dualling, would cut congestion and carbon.

Hugh Jaeger, Chairman, Bus Users Oxford