A4
A4 | ||||||||||||||||||||||
Location Map ( geo) | ||||||||||||||||||||||
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From: | London (TQ313815) | |||||||||||||||||||||
To: | Avonmouth (ST516785) | |||||||||||||||||||||
Distance: | 129.8 miles (208.9 km) | |||||||||||||||||||||
Meets: | M4, M5, M25, M49 | |||||||||||||||||||||
Primary Destinations | ||||||||||||||||||||||
Bristol • Maidenhead • Reading • Slough • Hounslow • Bath • Chippenham • Marlborough • Newbury • The City • Central London • Hammersmith • West End • London • Heathrow Airport | ||||||||||||||||||||||
Highway Authorities | ||||||||||||||||||||||
National Highways • Transport for London • Bath and North East Somerset • Bristol • Buckinghamshire • Reading • Slough • West Berkshire • Wiltshire • Windsor and Maidenhead • Wokingham | ||||||||||||||||||||||
Traditional Counties | ||||||||||||||||||||||
Berkshire • Buckinghamshire • Gloucestershire • Middlesex • Somerset • Wiltshire | ||||||||||||||||||||||
Route outline (key) | ||||||||||||||||||||||
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This article is about the British A4. You may be looking for the Northern Irish, Manx or Jersey road with this number.
Route
The A4 was the main road from the west of England to London before the coming of the M4. Its route from Avonmouth to London passes through the cities of Bristol and Bath, and the towns of Chippenham, Calne, Marlborough, Hungerford, Newbury, Reading, Maidenhead and Slough. It partly follows the route of the Great Western Main Line.
For more detail on the western end of the route, see A4/Avonmouth - Bath and A4/Bath - Chippenham. For more detail at the London end, see A4/Great West Road. Other sections are awaiting expansion as below.
The London-Bristol trunk road, created in 1936, followed the A4 throughout its route.
A4 individual sections
- A4/Avonmouth - Bath
- A4/Bath - Chippenham
- A4/Chippenham - Marlborough (awaiting expansion)
- A4/Marlborough - Newbury (awaiting expansion)
- A4/Newbury - Reading (awaiting expansion)
- A4/Reading - Slough (awaiting expansion)
- A4/Slough - London (awaiting expansion)
- A4/Great West Road
History
Unlike fellow single digit Ax roads, the A4 has fewer changes. This is mostly due to the fact that the M4 follows closely to the route of the A4. Also of the other single digit Ax Roads, it is the only one to be extended since classification.
Notable locations and improvements
Hyde Park Corner
At Hyde Park Corner, the A4 takes the main line and it goes under it. This was built in the early sixies.
Chiswick Roundabout
The Chiswick Roundabout is where the A4 becomes the M4. It is also the meeting point of the North & South Circular roads.
Maidenhead Bridge
The Maidenhead Bridge is the A4's crossing of the River Thames. It is in the town of the same name.
Newbridge
The Newbridge in Bath is one of the oldest bridges in Bath. It was opened in 1736.
Opening Dates
Month | Year | Section | Notes |
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1925 | Brentford Bypass | Great West Road. Officially opened by King George V on 30 May 1925. | |
1928 | Colnbrook Bypass | Opened on 18 June 1928. | |
1928 | Twyford Bypass | Opened on 10 September 1928. | |
1942 | Cromwell Road Extension | Warwick Road to North End Road (unclassified when open). | |
1956 | Cromwell Road Extension | Chiswick Lane to the Hammersmith Flyover junction. | |
1959 | Cromwell Road Extension | Hammersmith Flyover junction to North End Road (parts may have opened earlier). | |
1959 | Newbury Inner Relief Road | Stage 1 (east -west) opened on 16 March 1959. | |
1959 | Chiswick Flyover | Dual carriageway realignment and new junction. Opened on 30 September 1959. | |
1961 | Hammersmith Flyover | Dual carriageway. Opened on 16 November 1961. | |
1966 | Keynsham Bypass | Dual carriageway. Opened on 26 July 1966. | |
1971 | Theale Bypass | Dual carriageway. Fully opened on 13 December 1971. | |
1971 | Calne Inner Relief Road | May have opened in 1972 (see Network changes - 1970s). | |
1996 | Batheaston Bypass | Dual carriageway. Opened in May 1996. |
Grid References
Links