A420 road
Major junctions
West end:	Old Market Street, Bristol
	A4044 road A4320 road A431 road A4017 road A4174 road A4175 road A46 road A350 road A4 road A3102 road A419 road A417 road A415 road A338 road A34 road A4144 road A4158 road A4142 road A40 road
East end:	Headington in Oxford
Location
Primary destinations:	Chippenham Swindon
Road network
Roads in the United Kingdom Motorways • A and B road zones

The A420 is a road between Bristol and Oxford in England. Between Swindon and Oxford it is a primary route.

Present route[link]

Since the opening of the M4 motorway, the road is in two sections. The first section begins on Old Market Street near the centre of Bristol, it passes through Kingswood before leaving the city on the east side. From here it travels eastward over the southern part of the Cotswolds, to the north of Bath, to Chippenham in Wiltshire.

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 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 new^{[date missing]} section by-passes Faringdon, just south of Folly Hill and crosses the A417.

The A420 then travels the corallian limestone 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.

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 on Osney Bridge and reaches central Oxford. 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.^[1] The road then crosses Magdalen Bridge to St Clements and East Oxford and ascends the notoriously steep Headington Hill to the suburb of Headington before terminating at the Green Road roundabout, where it meets the A40 and the Oxford Ring Road.

Large vehicles such as lorries are advised by large signs at Oxford and Swindon not to take this route and use the alternative A34, from Junction 13 of the M4.

History[link]

When first classified in 1922, the A420 ran between Chippenham and Botley, near Oxford. The road between Bristol and Chippenham was the A430.^[2] The two roads were later joined and the A430 renumbered A420. The road from Botley through Oxford to Headington 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 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.

Site of Fastest Speeding Ticket[link]

The A420 near Kingston Bagpuize in Oxfordshire was the site of the crime of the fastest driver 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 172 miles per hour (277 km/h) in a Porsche 911 Turbo that he had taken without permission from his employer, a luxury car hire firm.^[3] Brady was disqualified from driving and sentenced to 10 weeks in prison.^[3]

References[link]

1. ^ Email from Oxfordshire County Council Highways, 23 October 2007
2. ^ 1922 road list
3. ^ ^{a b} "Jail for 172mph Porsche motorist". BBC. 24 September 2007. http://news.bbc.co.uk/2/hi/uk_news/england/oxfordshire/7009923.stm. Retrieved 16 January 2011. 

v t e A roads in Zone 4 of the Great Britain road numbering scheme A4 A40 A41 A42 A43 A44 A45 A46 A47 A48 A49 A403 A404 A405 A406 A412 A413 A414 A415 A417 A418 A419 A420 A421 A422 A423 A425 A426 A427 A428 A429 A431 A432 A433 A435 A441 A442 A444 A445 A446 A448 A449 A452 A453 A454 A456 A458 A461 A465 A468 A469 A470 A472 A473 A474 A475 A476 A477 A478 A482 A483 A484 A485 A486 A487 A488 A489 A490 A491 A493 A494 A496 A497 A498 A499 A4005 A4006 A4008 A4010 A4012 A4018 A4025 A4032 A4037 A4040 A4042 A4050 A4053 A4054 A4055 A4059 A4060 A4061 A4063 A4067 A4069 A4074 A4076 A4080 A4085 A4094 A4103 A4107 A4109 A4113 A4117 A4118 A4119 A4123 A4130 A4133 A4135 A4136 A4138 A4142 A4146 A4148 A4150 A4155 A4160 A4161 A4169 A4173 A4174 A4202 A4212 A4216 A4217 A4221 A4226 A4230 A4232 A4234 A4240 A4241 A4260 A4289 A4361 A4400 A4536 A4540 List of A roads in Zone 4 List of B roads in Zone 4

Coordinates: 51°34′46″N 1°43′20″W / 51.57931°N 1.72211°W / 51.57931; -1.72211