The A420 is a road between
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city i ...
and
Oxford
Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the Un ...
in England. Between
Swindon and Oxford it is a
primary route.
Present route
Since the opening of the
M4 motorway, the road has been in two sections. The first section begins on
Old Market Street near the centre of
Bristol
Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city i ...
, and passes through
Kingswood before leaving the city on the east side. From here it travels eastward over the southern part of the
Cotswolds
The Cotswolds (, ) is a region in central-southwest England, along a range of rolling hills that rise from the meadows of the upper Thames to an escarpment above the Severn Valley and Evesham Vale.
The area is defined by the bedrock of Ju ...
, to the north of
Bath
Bath may refer to:
* Bathing, immersion in a fluid
** Bathtub, a large open container for water, in which a person may wash their body
** Public bathing, a public place where people bathe
* Thermae, ancient Roman public bathing facilities
Plac ...
, to
Chippenham in
Wiltshire
Wiltshire (; abbreviated Wilts) is a historic and ceremonial county in South West England with an area of . It is landlocked and borders the counties of Dorset to the southwest, Somerset to the west, Hampshire to the southeast, Gloucestershir ...
.
The second section starts at a junction with the
A419 east of Swindon. It then travels under the
Great Western Main Line at the twin-arch
Acorn Bridge
The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally
two seeds), enclosed in a tough, leathery shell, and borne ...
and by-passes
Shrivenham (the road originally went through
Shrivenham, but the by-pass was built in the mid-1980s) and
Watchfield, then on towards
Faringdon in the
Vale of White Horse. A further by-pass section, opened in 1979,
avoids the centre of Faringdon, passing just south of
Folly Hill
Faringdon is a historic market town in the Vale of White Horse, Oxfordshire, England, south-west of Oxford, north-west of Wantage and east-north-east of Swindon. It extends to the River Thames in the north; the highest ground is on the Ridg ...
and crossing the
A417
The A417 is a main road in England running from Streatley, Berkshire to Hope under Dinmore, Herefordshire. It is best known for its section between Cirencester and Gloucester where it has primary status and forms part of the link between the m ...
.
The A420 then travels the
corallian limestone
The Corallian Group or Corallian Limestone is a geologic group in England. It is predominantly a coralliferous sedimentary rock, laid down in the Oxfordian stage of the Jurassic. It is a hard variety of "coral rag". Building stones from this geo ...
ridge that forms the north-west boundary of the Vale of White Horse, passing
Littleworth,
Buckland and
Longworth. A
dual-carriageway section by-passes
Southmoor and
Kingston Bagpuize on its way to
Oxford
Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the Un ...
. Most of the road between Swindon and Oxford, apart from the dual carriageway sections and a short section around Faringdon, is limited to 50 mph (80 km/h).
A further dual-carriageway section bypasses
Cumnor Hill, to give a view of the "City of Dreaming Spires" that is Oxford from the west. It then passes the
Oxford Ring Road, through the suburb of
Botley and down the
Botley Road. It crosses the
River Thames
The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the ...
on
Osney Bridge and reaches central Oxford after passing under the
Cherwell Valley Line next to
Oxford station. Within Oxford, it is routed along
Oxpens Road, then Thames Street, parts of
St Aldate's then the
High Street, which is closed to most motor traffic during the day. The road then crosses
Magdalen Bridge to
St Clements and
East Oxford and ascends the notoriously steep
Headington Hill to the suburb of
Headington
Headington is an eastern suburb of Oxford, England. It is at the top of Headington Hill overlooking the city in the Thames valley below, and bordering Marston, Oxford, Marston to the north-west, Cowley, Oxfordshire, Cowley to the south, and Bar ...
before terminating at the Headington Roundabout (known locally as the Green Road roundabout), where it meets the
A40 and the Oxford Ring Road (designated the A4142).
Large vehicles such as lorries are advised by large signs at Oxford and Swindon not to take this route and use the alternative A34 and M4 route to Swindon. This is not enforced and the road is often heavily congested due to slow HGVs taking the shorter A420 route. The road has a poor accident record and this coupled with heavy peak time traffic has caused it to be nicknamed the 'A420 Road to Hell' in the local media. A survey in February 2018 claimed that it is the most dangerous A road in
South East England
South East England is one of the nine official regions of England at the first level of ITL for statistical purposes. It consists of the counties of Buckinghamshire, East Sussex, Hampshire, the Isle of Wight, Kent, Oxfordshire, Berkshi ...
.
History
What is now the A420 was established in the early 18th century as a direct route between Chippenham and Bristol via Tog Hill, avoiding the older and more established route via Bath (now the
A4). It was an important road for Bristol, whose communications with Bath had been disputed and difficult. After the Bath Road was turnpiked in 1707, the Bristol Trust attempted to turnpike the direct road in 1727, but faced opposition from colliers at
Kingswood, and the road was not sufficiently improved until the 1740s.
When first classified in 1922, the A420 ran between Chippenham and
Botley, near Oxford, while the road between Bristol and Chippenham was the A430. The two roads were later joined and the A430 renumbered A420. The road from Botley through Oxford to
Headington
Headington is an eastern suburb of Oxford, England. It is at the top of Headington Hill overlooking the city in the Thames valley below, and bordering Marston, Oxford, Marston to the north-west, Cowley, Oxfordshire, Cowley to the south, and Bar ...
was originally part of the A40. When the northern Oxford bypass was built in the 1930s, the A40 was rerouted along the bypass and the road through Oxford was renumbered A420.
As a result of the building of the M4 motorway in the early 1970s and subsequent road modernisation, the A420 between Chippenham and Swindon lost its identity. From Chippenham to
Lyneham through
Sutton Benger and to the north of
RAF Lyneham and its limestone ridge, it became the
B4069. From Lyneham to Swindon it became part of the
A3102. From Swindon through
Stratton St Margaret to the A419 it became the A4312.
Matches between rival football clubs
Oxford United and
Swindon Town are sometimes referred to as the "A420 derby".
Landmarks
Sir Bevil Grenville's Monument on
Lansdown Hill is near the A420.
Site of fastest speeding ticket
The A420 near
Kingston Bagpuize in Oxfordshire was the site of the fastest speeding offence ever caught in a routine speed check in the UK. On 27 January 2007, Timothy Brady, a 33-year-old man from
Harrow, London, was clocked driving at in a
Porsche 911 Turbo that he had taken without permission from his employer, a luxury car hire firm.
Brady was disqualified from driving and sentenced to 10 weeks in prison.
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References
{{DEFAULTSORT:4-0420
Roads in England
Roads in Bristol
Transport in Wiltshire
Roads in Oxfordshire
Transport in Oxford