A40 (England)

A40 (England)
Country	England
Route	40
Length mi	125
Direction a	West
Terminus a	Cartmar, Wales
Direction b	East
Terminus b	London
Cities	Oxford, Cheltenham, Gloucester, High Wycombe, Uxbridge

A40 (England) The A40 in England is a major trunk road linking London with the English–Wales border near Goodwick and serving key urban centres including High Wycombe, Oxford, Cheltenham, and Gloucester. Running roughly west–east, the route provides interurban connectivity between the M25 motorway, M40 motorway, and arterial routes into Central London and western Wales. The road passes through areas administered by authorities such as Buckinghamshire Council, Oxfordshire County Council, Gloucestershire County Council, and Royal Borough of Kingston upon Thames.

Route

The A40 begins in Central London near Oxford Street and proceeds west via Marylebone, Notting Hill, and Hammersmith, intersecting major corridors such as the A4 (M) and providing access to Heathrow Airport via feeder routes and connections to the M4 motorway. West of the capital the carriageway traverses the London Borough of Hillingdon toward Uxbridge and High Wycombe before joining the M40 motorway near Stokenchurch and Wheatley. Through Oxford the A40 skirts the city along the Oxford Ring Road and proceeds westward across Oxfordshire through villages such as Eynsham and Taynton. Beyond Cheltenham and Gloucester the road continues through Herefordshire-bordering landscapes to link with cross-border routes at the Wales–England border, interfacing with Welsh trunk roads toward Cardiff, Swansea, and Narberth.

History

The modern A40 overlays sections of historic coaching and stagecoach routes that linked London to Oxford and the West Country since the 17th and 18th centuries, paralleling routes used during the era of Turnpike trusts and the expansion of the Great Western Railway network. Twentieth-century classification under the Roads Act 1920 and subsequent Ministry of Transport numbering established the A40 as a primary highway; post‑war reconstruction and the rise of motoring prompted bypasses around towns including Beaconsfield and Cheltenham. The construction of the M40 motorway from Junction 1 to Junction 9 in the 1960s–1990s altered long‑distance traffic patterns, with parts of the original A40 reclassified as local A‑roads such as the A329 and A418. Urban upgrades in West London—notably the westward extension from Shepherd's Bush—and the development of the Oxford Ring Road reflect coordinated schemes by bodies such as Transport for London and county highways authorities.

Major junctions and sections

Key interchanges include the A40’s junction with the A4 (M) in west London, the intersection at High Wycombe with the A404, the linkages to the M40 motorway at Stokenchurch and Handy Cross, and the interchange near Oxford where the A40 meets the A34 and M40 spur roads. Notable sections comprise the Westway elevated route through Notting Hill, the dual carriageway trunk between Cheltenham and Gloucester serving M5 motorway connections at Junction 11A, and rural stretches across Cotswolds landscapes adjacent to Northleach and Burford. Urban bypasses at Beaconsfield and the Eynsham bypass are significant for regional traffic relief, while the A40’s approach into London Paddington forms a primary feeder for commuters and freight to Marylebone and the West End.

Traffic and safety

Traffic volumes vary from high-density urban flows in West London—in proximity to Heathrow Airport and Hammersmith—to moderate interurban volumes on the Cotswolds sections managed by Gloucestershire County Council and Oxfordshire County Council. Collision hotspots historically include complex junctions such as the High Wycombe interchange and the A40/A44 convergence near Oxford, prompting speed management, carriageway realignment, and junction signalisation overseen by agencies including National Highways and local highway authorities. Freight movements linking the M5 motorway and M4 motorway corridors contribute to heavy goods vehicle presence; peak congestion tends to coincide with commuting periods and seasonal tourism toward Cheltenham Racecourse and Cotswold attractions.

Public transport and cycling provisions

Along urban stretches in London the A40 corridor supports multiple Transport for London bus routes, including express services feeding Marylebone and Bond Street stations, and interfaces with London Underground lines such as the Central line and Circle line near interchange hubs. Between Oxford and Cheltenham, intercity and regional bus operators including Stagecoach Group and National Express run services that use sections of the A40 for coach connections to Birmingham and Cardiff. Cycling infrastructure exists on parts of the route where local authorities have installed advisory lanes, segregated cycleways, and Quietways linking into networks such as the National Cycle Network and routes promoted by Sustrans, notably around Oxford and sections of the Cotswold approach. Park-and-ride facilities adjacent to the A40 at Oxford and Gloucester integrate multimodal travel policies championed by county councils.

Future developments and proposals

Planned and proposed schemes affecting the A40 include capacity and safety upgrades promoted by National Highways and county councils, possible junction remodelling near Stokenchurch to improve access to the M40, and local authority plans for bypass improvements at Eynsham and urban traffic reduction measures in West London led by Transport for London. Environmental assessments and public consultations coordinated with bodies such as Historic England and Natural England influence proposals in ecologically sensitive Cotswolds areas. Longer‑term strategic transport planning documents from Department for Transport and regional planning authorities consider modal shift measures, including enhanced bus priority and cycling improvements, to reduce congestion and carbon emissions along the corridor.

Category:Roads in England