M4 motorway
M4 | ||||
---|---|---|---|---|
Prince of Wales Bridge looking towards Wales | ||||
Route information | ||||
Part of E30 | ||||
Maintained by Pont Abraham 51°44′42″N 4°03′54″W / 51.7451°N 4.0651°W | ||||
Location | ||||
Country | ||||
Road network | ||||
|
The M4, originally the London-South Wales Motorway, is a
The line of the motorway from
The M4 is the only motorway in Wales apart from its two spurs: the A48(M) and the M48. The major towns and cities along the route—a distance of approximately 189 miles (304 km)—include Slough, Reading, Swindon, Bristol, Newport, Cardiff, Bridgend, Port Talbot and Swansea.
History
A new road from London to South Wales was first proposed in the 1930s. In 1956 the
The Chiswick flyover, a short section of elevated dual-carriageway, not originally classed as a motorway, opened in 1959 to reduce the impact of traffic travelling between central London and the west.[2][3]
The
The English section of the motorway was completed on 22 December 1971 when the 50-mile (80 km) stretch between junctions 9 and 15 Maidenhead and Swindon) was opened to traffic.[6] The Welsh section was largely completed between 1970 and 1980, though a non-motorway section remained across the Briton Ferry bridge until 1993, when a second motorway-only bridge opened.
In 1996, the Second Severn Crossing opened with new link motorways on either side of the estuary to divert the M4 over the new crossing. At the same time, the original route over the Severn Bridge was redesignated the M48, and the M49 was opened to link the new crossing with the M5 at Avonmouth.[7] The new M49 shortened the route between South Wales and the South West, and reduced traffic at the busy M4/M5 junction at Almondsbury.
After completion
In April 2005, speed checks carried out by police camera vans between junction 14 and junction 18 led to a public protest, involving a "go-slow" of several hundred vehicles along the affected sections of the motorway.[8]
Between 2007 and January 2010, the section from
During 2009, the Newport section of the motorway between junctions 23a and 29 was upgraded with a new concrete central barrier. In February 2010, it was proposed that the M4 in South Wales would become the first
Between 2008 and 2010, junction 11 was extensively remodelled with a new four-lane junction, two new road bridges and other works.
Former bridge tolls
Tolls were charged on the Severn Bridge(s) from opening until 2018. In 1966 the toll was 12+1⁄2
Timeline of construction
Year opened | 1961 | 1963 | 1965 | 1966 | 1967 | 1971 | 1972 | 1977 | 1980 | 1994 |
---|---|---|---|---|---|---|---|---|---|---|
Section(s) | J7–9 | J5–7 | J1–5 | J18–23 J39–41 |
J22–28 | J9–18 | J44–46 | J28–29 J32–35 J37–39 J46–49 |
J29–32 J35–37 |
J41–44 |
Maintenance
Maintenance of the Second Severn Crossing and the 123 miles (198 km) of motorway in England is the responsibility of National Highways.[24] The 76 miles (122 km) in Wales is the responsibility of the South Wales Trunk Road Agent.[25]
Features
Speed limits
For the majority of its length, the
- 40 miles per hour (64 km/h) on the Chiswick Flyoverwithin London in both directions.
- 60 miles per hour (97 km/h) between junction 4 and the Chiswick Flyover, eastbound only.
- 50 miles per hour (80 km/h) on the Port Talbot elevated section between junction 40 and junction 41. The fixed speed camera was removed in 2006 as it was believed to be causing tailbacks. In July 2014, an average speed camera system was installed; it generated around £500,000 in fines in the first six months.[26][27]
- 50 miles per hour (80 km/h) between junctions 24 and 28 at Newport.
Smart motorway
The M4 has one section of smart motorway, between junctions 19 (M32) and 20 (M5) north of Bristol, where there are variable speed limits and a part-time hard-shoulder. Completion was in summer 2014. Another section between junctions 24 and 29 in Newport had variable speed limits until 2021, when it was changed to a permanent 50 mph limit with average speed cameras.[28]
In 2010, it was announced that the motorway would be changed to a smart motorway between junctions 3 and 12. With a length of 32 miles (51 km), this will be the longest smart motorway scheme in the United Kingdom. Work started in autumn 2018 and is expected to be completed in March 2022 at a cost of £848 million.[29][30]
Brynglas tunnels
The
Bus lane
In June 1999, the M4 bus lane was created on the third lane between junctions 2 and 3, initially as a pilot scheme and then a permanent arrangement from 2001. A lower speed limit was introduced along this section at the same time.[34] The 3+1⁄2-mile (5.6 km) bus lane was on the eastbound carriageway; from the western end of the Chiswick Flyover near Brentford to junction 3 (A312), covering part of the 15-mile (24 km) journey between Heathrow Airport and central London. The lane which had no intermediate exits was for use by buses, coaches, motorcycles, emergency vehicles and licensed taxis but not mini-cabs.[35]
In December 2010, the bus lane was suspended for 18 months.[36][37] It was reinstated temporarily for the 2012 Summer Olympics and then permanently decommissioned.[38]
Porous road surface
Near junction 35 of the M4, there is a stretch of the motorway that has a surfacing of porous
Elevated and heated section
The elevated section of the M4 in West London, built in the 1960s, is mostly directly above the A4 and extends over parts of Brentford's Golden Mile. This section was designed to have a heated road surface to reduce icing in winter.[40][41]
Four-level stack interchanges
The M4 has two of the three four-level stack interchanges in the UK, including the first UK example at junction 20, the "Almondsbury Interchange" with the M5. The other is at junction 4b, the "Thorney Interchange" with the M25; this interchange has to make provision for a railway line passing beneath the M4. Due to the nature of these junctions, one cannot make a U-turn at either of them.
Notable junctions
Junction 8/9 near
Plans for the "missing" Junction 31, also known as the Thornhill interchange, for which planning permission was originally granted in September 1991 (but subsequently expired), were rekindled after proposals for a new business park on a 125 acres (51 ha) site north of the M4 were submitted in 2007 to Cardiff Council.[43] The developers of the business park, St Modwen Developments, would likely fund the new junction, which would be on the A469.[44] A freedom of information request in 2010 to Cardiff Council shows that whilst the land that would enable this junction should continue to be strategically protected, the decision to formally abandon the proposed Junction 31 Thornhill was made in October 2007 and there had been no subsequent mention of it in Cardiff Council Strategic or Planning meetings since.[45] In South Wales, the M4 has to thread its way through mountainous terrain and built-up areas, so there are some unusual junction layouts. Junction 27 (High Cross) is a normal grade-separated roundabout junction, but has severe space constraints: traffic joining the motorway must initially travel in the opposite direction to the intended direction of travel, before making a sharp left-hand turn from the slip road onto the motorway. At the time of construction, junction numbers 30 and 31 were reserved for future intermediate interchanges. Junction 30 (Cardiff Gate) has since been added, but there are no current plans to construct Junction 31 (A469 road). Junction 39 can only be used to access the motorway from a single slip road onto the westbound carriageway from the A48 at junction 38. There is no exit from the motorway at this junction.[46]
Junction 41 comprises two different junctions; one for local traffic to and from the west and one from the east. The former leads to and from a spur leading to the roundabout in Briton Ferry, formerly known as junction 41a, and the original bridge over the River Neath, which would allow access onto the stretch of the M4 from junction 43 westward. The second, eastern junction leads to and from the A48 towards Port Talbot. As a result, one can travel for almost 2 miles (3.2 km) on the motorway in either direction, both joining and then leaving the motorway at junction 41. Junction 44 is unusual in that the eastbound entrance dives under the inside of the junction, effectively creating a "right-turn" on a roundabout. Similarly, slip roads pass under or over the main motorway at junctions 41 and 42.[47]
There have been calls to close the
Relief road
On 5 June 2019, the
List of junctions
This article contains a bulleted list or table of intersections which should be presented in a properly formatted junction table.(December 2021) |
M4 motorway | |||||
mile | km | Eastbound exits (B carriageway) | Junction | Westbound exits (A carriageway) | |
---|---|---|---|---|---|
7.3 | 11.8 | Road continues as A4 to Central London | J1 [coord 1] |
Start of motorway | |
8.3 8.5 |
13.4 13.7 |
A315
|
J2 | Staines, Hounslow, Brentford A4 | |
12.5 12.8 |
20.1 20.6 |
Heston services
|
Services | Heston services
| |
13.4 13.7 |
21.5 22.1 |
Heathrow (Terminals 4, 5 & Cargo), Hayes, Harrow, Hounslow A312 | J3 | Heathrow (Terminals 4, 5 & Cargo), Hayes, Harrow, Hounslow A312 | |
15.2 15.7 |
24.5 25.2 |
Heathrow (Terminals 2 & 3) (A4) Uxbridge A408 |
J4a | A408
| |
16.8 17.7 |
27.0 28.5 |
J4b Thorney Interchange [coord 2] |
Heathrow (Terminals 4, 5 & Cargo), Gatwick, Dartford, Oxford, Watford, Stansted, (M3), (M23), (M20), (M40), (M1), (A1(M)), (M11), M25 | ||
Entering Greater London | Entering Berkshire | ||||
19.1 19.5 |
30.7 31.4 |
B470
|
J5 | B470
| |
22.9 23.2 |
36.8 37.4 |
A322
|
J6 | A322
| |
Entering Berkshire | Entering Buckinghamshire | ||||
24.7 25.0 |
39.8 40.3 |
Slough (West) A4 | J7 Trumpet interchange
|
Slough (West) A4 | |
Entering Buckinghamshire | Entering Berkshire | ||||
27.8 28.2 |
44.7 45.4 |
J8/9 | |||
35.0 35.8 |
56.4 57.6 |
Reading (East), Wokingham, Bracknell A329(M) | J10 Partial cloverleaf interchange |
Reading (East), Wokingham, Bracknell A329(M) | |
40.6 41.2 |
65.4 66.3 |
Basingstoke, Reading (Central & South) A33 | J11 | Basingstoke, Reading (Central & South) A33 | |
43.5 43.8 |
70.0 70.5 |
Reading services | Services | Reading services | |
45.3 45.7 |
72.9 73.5 |
Reading (West), Theale A4 | J12 | Reading (West), Theale A4 | |
56.9 57.2 |
91.5 92.1 |
) | J13 Services [coord 3] |
) | |
64.4 64.8 |
103.7 104.3 |
Hungerford, Wantage A338 | J14 | Hungerford, Wantage A338 | |
68.7 | 110.5 | Membury services | Services | Membury services | |
Entering Berkshire | Entering Wiltshire | ||||
76.4 77.1 |
122.9 124.0 |
) | J15 | A346
| |
82.4 82.8 |
132.6 133.2 |
A3102
|
J16 | A3102
| |
94.8 95.3 |
152.5 153.4 |
Chippenham A350 Cirencester A429 |
J17 | Chippenham A350 Cirencester A429 | |
96.7 | 155.7 | Leigh Delamere services | Services | Leigh Delamere services | |
Entering Wiltshire | Entering South Gloucestershire | ||||
104.9 105.6 |
168.8 170.0 |
A46
|
J18 | A46
| |
112.8 113.2 |
181.5 182.1 |
Bristol M32 | J19 | Bristol M32 | |
115.8 116.3 |
186.3 187.2 |
The South West, Bristol (West), The Midlands, Gloucester, Bristol Airport , M5 | J20 Almondsbury Interchange [coord 4] |
The South West, Bristol (West) M5(S) The Midlands, Gloucester M5(N) | |
117.7 189.5 |
189.5 190.0 |
No access | J21 | Chepstow M48 | |
121.3 121.6 |
195.2 195.7 |
Avonmouth, Bristol Airport , Weston-super-Mare M49 | J22 | Avonmouth M49 | |
121.7 124.1 |
195.9 199.8 |
Entering South Gloucestershire | Second Severn Crossing [coord 5] |
Entry into Wales | |
Entry into England | Entering Monmouthshire | ||||
127.0 | 204.4 | No toll plaza | Bridge Toll | Former toll plaza (closed Dec 2018) | |
129.2 | 208.0 | Chepstow M48 | J23 | No access | |
131.4 132.2 |
211.4 212.8 |
A4810
Magor services |
J23A Services |
A4810
Magor services | |
Entering Monmouthshire | Entering Gwent | ||||
134.8 135.6 |
217.0 218.3 |
) | J24 | ||
137.9 | 222.0 | No access | J25 | B4596
| |
138.3 | 222.6 | No access | J25A | Newport (East), Cwmbran A4042 | |
138.8 139.1 |
223.4 223.8 |
Brynglas Tunnels | Tunnel | Brynglas Tunnels | |
139.1 139.5 |
223.8 224.5 |
A4051
|
J26 | A4051
| |
140.8 141,4 |
226.6 227.6 |
B4591
|
J27 | B4591
| |
142.0 142.9 |
228.5 230.0 |
A467
|
J28 | A467
| |
143.6 | 231.1 | No access | J29 | Cardiff (South & East) A48(M) | |
Entering Gwent | Entering South Glamorgan | ||||
146.6 147.3 |
236.0 237.0 |
Cardiff (East) A4232 Cardiff Gate services |
J30 Services |
Cardiff (East) A4232 Cardiff Gate services | |
Non- existent | J31 | Non-existent | |||
151.9 244.5 |
244.5 246.1 |
Merthyr Tydfil, Cardiff (North & Central) A470 | J32 | Cardiff (North & Central), Merthyr Tydfil A470 | |
155.4 156.0 |
250.1 251.1 |
Cardiff (West), Barry, Penarth A4232 Cardiff Airport Cardiff West services |
J33 Services |
Cardiff (West), Barry, Penarth A4232 Cardiff Airport Cardiff West services | |
157.5 158.1 |
253.5 254.4 |
Llantrisant, Rhondda A4119 Royal Glamorgan Hospital |
J34 | Llantrisant, Rhondda A4119 Royal Glamorgan Hospital | |
Entering South Glamorgan | Entering Mid Glamorgan | ||||
163.9 164.4 |
263.7 264.5 |
Pen-coed A473 | J35 | Bridgend, Pen-coed A473 | |
167.5 168.3 |
269.6 270.8 |
Bridgend A4061 Maesteg A4063 Princess of Wales Hospital Sarn Park services |
J36 Services |
Bridgend A4061 Maesteg A4063 Princess of Wales Hospital Sarn Park services | |
172.8 173.5 |
278.1 279.3 |
A4229
|
J37 | A4229
| |
Entering Mid Glamorgan | Entering West Glamorgan | ||||
177.0 177.3 |
284.9 285.3 |
Port Talbot A48 | J38 | Port Talbot A48 | |
178.3 | 286.9 | No access (on-ramp only) | J39 | No access | |
179.7 179.9 |
289.2 289.6 |
Port Talbot A4107 | J40 | Port Talbot A4107 | |
180.9 181.3 |
291.1 291.8 |
Port Talbot A48 | J41 | Briton Ferry A48 | |
183.9 184.9 |
295.9 297.3 |
Briton Ferry A48 Swansea (South) A483 |
J42 | Swansea (South) A483 | |
184.9 185.7 |
297.5 298.8 |
Neath, Merthyr Tydfil A465 | J43 | Neath, Merthyr Tydfil A465 | |
187.0 187.4 |
300.9 301.6 |
Swansea (East) A48 | J44 | Swansea (East) A48 | |
188.8 189.3 |
303.9 304.7 |
A4067
|
J45 | A4067
| |
190.8 191.4 |
307.0 308.0 |
J46 | |||
192.4 193.1 |
309.6 310.7 |
Swansea (West) A483 Gorseinon A48 Swansea services |
J47 Services |
Swansea (West) A483 Gorseinon A48 Swansea services | |
Entering West Glamorgan | Entering Carmarthenshire | ||||
196.4 197.1 |
316.0 317.2 |
Pontarddulais, Llanelli A4138 | J48 | Pontarddulais, Llanelli A4138 | |
199.2 | 320.6 | Start of motorway | J49 Terminus Services [coord 6] |
Motorway terminates at a roundabout: Pont Abraham services
| |
- Coordinate list
- ^ 51°29′22″N 0°16′40″W / 51.48944°N 0.27778°W Eastern end of M4
- ^ 51°29′41″N 0°29′44″W / 51.49472°N 0.49556°W Thorney Interchange – Intersection of M25 and M4
- ^ 51°27′14″N 1°18′52″W / 51.45389°N 1.31444°W Intersection of M4 and A34 (E05)
- ^ 51°33′01″N 2°33′11″W / 51.55028°N 2.55306°W Almondsbury Interchange – Intersection of M4 and M5
- ^ 51°34′21″N 2°41′31″W / 51.57250°N 2.69194°W Second Severn Crossing
- ^ 51°44′42″N 4°03′54″W / 51.74500°N 4.06500°W Western end of M4
Data
E30
Although not signed, European route E30 includes most of the M4. The entire route runs 6,530 kilometres (4,060 mi) between Cork in Ireland and Omsk in Russia.
Major incidents and accidents
- In June 1984 a crash near Maidenhead resulted in 13 deaths.[62]
- In March 1991, ten people died in the 1991 M4 motorway crash near Hungerford. The crash involved 51 vehicles in foggy conditions.[63]
- In May 1995 a coach carrying Royal British Legion members left the M4 close to the Severn Bridge, resulting in 10 deaths.[62]
- In April 1998, drummer Cozy Powell died following a car accident on the M4 near Bristol.
- In July 2002, Gus Dudgeon, a music producer known for his work with Elton John, and his wife died when the car he was driving veered off the M4 between Reading and Maidenhead. The inquest recorded a verdict of accidental death.[64]
See also
- M4 corridor
- M4 Thames Bridge, Maidenhead
- List of motorways in the United Kingdom
- Transport in Wales
References
- ^ "The M4 London to South Wales Motorway. Holyport to Tormarton". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 3 October 2010.
- ^ Curtis, Nick (1 October 2009). "The 'sweet little Chiswick Flyover' hits 50". This Is London. Archived from the original on 21 March 2011. Retrieved 3 March 2012.
The showbiz opening on 30 September 1959 was therefore a shrewd publicity stunt by Alderton's managing director, J E Dayton. It worked.
- ^ "The Oldest Motorway". The Motorway Archive Trust. Archived from the original on 22 January 2010. Retrieved 3 March 2012.
- ^ "Vandals' Damage To Motorway Cost Thousands Of Pounds". The Times. No. 56277. 23 March 1965. p. 16. Retrieved 1 March 2020.
- ^ "The M4 in Wales". The Motorway Archive Trust. Archived from the original on 22 January 2011. Retrieved 1 October 2010.
- The Motor. nbr 3625: 30. 23 December 1971.
- ^ "The Motorway Archive: M4 Second Severn Crossing". Iht.org. 28 April 1992. Archived from the original on 7 February 2012. Retrieved 31 December 2011.
- ^ "Drivers hold M4 speed camera demo". BBC News. 30 April 2005.
- ^ "M4 Motorway Widening". Archived from the original on 15 January 2008. Retrieved 20 November 2010.
- ^ "M4 in Wales to be 'hydrogen highway,' ministers to say". BBC News. 12 February 2010. Retrieved 12 February 2010.
- ^ Fraser, Douglas (8 September 2009). "'Hydrogen highway' plans backed". BBC News. Retrieved 12 February 2010.
- ^ "M4 Junction 11 Improvement Scheme". Highways Agency. Archived from the original on 26 June 2009.
- ^ "M4 Junction 11 Improvements". Reading Borough Council. Archived from the original on 13 July 2010.
- ^ "Reading is the fastest-growing economic centre in UK". Reading Chronicle. 10 July 2007.
- ^ "M4 VICKERS MACHINE GUN PILLBOX, PILLBOX STUDY GROUP". Pillbox-study-group.org.uk. 11 April 2008. Archived from the original on 8 September 2012. Retrieved 31 December 2011.
- ^ "Severn tolls to be axed earlier than planned on 17 December". BBC News. 2 October 2018. Retrieved 21 January 2022.
- ^ "Dates:M4. Chiswick to Slough By-pass (J1 to J5)". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 13 March 2013.
- ^ "Dates:M4 Slough-Maidenhead By-pass (Junctions 5 to 7) Statistics and options". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 13 March 2013.
- ^ "Dates:M4. Maidenhead to Wickham (J8 to J14) Statistics and options". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 13 March 2013.
- ^ "Dates:The Aust (J21) to Wickham (J14) section of M4 Statistics and options". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 13 March 2013.
- ^ "Dates:M4 in Wales Statistics and options". The Motorway Archive Trust. Archived from the original on 24 June 2013. Retrieved 13 March 2013.
- ^ "History Overview". Severn River Crossing Plc. 2011. Archived from the original on 15 March 2013. Retrieved 16 March 2013.
- ^ "Second Severn Crossing, England and Wales – Halcrow Group". Halcrow.com. 29 October 2009. Archived from the original on 10 March 2010. Retrieved 16 March 2013.
- ^ Highways Agency: Our network Archived 14 March 2013 at the Wayback Machine. Retrieved 8 March 2013
- ^ "South Wales Trunk Road Agent (SWTRA)". Traffic Wales. Retrieved 24 October 2020.
- ^ "Average speed cameras for Port Talbot M4 stretch". BBC South West Wales. 14 July 2014. Retrieved 14 July 2014.
- ^ "M4 speed cameras generate half a million pounds". itv.com. 16 June 2015. Retrieved 5 March 2016.
- Highways Agency. Retrieved 18 February 2012.
- ^ "M4 junctions 3 to 12 smart motorway" (PDF). Highways Agency. Retrieved 27 December 2015.
- ^ England, Highways (20 May 2020). "M4 junctions 3-12: smart motorway - Highways England". highwaysengland.co.uk.
- ^ "Traffic chaos after M4 Brynglas tunnel lorry blaze". BBC News. 26 July 2011. Retrieved 9 April 2013.
- ^ "M4 tunnel fire: Brynglas tunnel reopens". BBC News. 29 July 2011. Retrieved 9 April 2013.
- ^ "M4 tunnel fire sparks relief road debate". BBC News. 27 July 2011. Retrieved 9 April 2013.
- ^ "U-turn". BBC. 18 January 2001. Retrieved 12 May 2010.
- ^ Edwards, Tom (11 September 2009). "M4 bus lane is 'barely enforced'". BBC News. Retrieved 12 May 2010.
- ^ "Stretch of M4 bus lane opens to all motorists". BBC News. 16 November 2010. Retrieved 16 November 2010.
- ^ "Work starts to remove M4 Bus Lane". Highways Agency. 12 November 2010. Archived from the original on 7 July 2012.
The suspension of the M4 Bus Lane is being carried out under an Experimental Order under the Road Traffic Regulation Act 1984
- ^ "Government to scrap M4 bus lane". BBC News. 1 October 2010. Retrieved 1 October 2010.
The controversial M4 bus lane is due to be scrapped at the end of the year. Under the plans, all motorists will be able to use the 3.5 miles (5.6 km) lane which operates on the London-bound carriageway from near Heathrow
- ^ "2006 Fourth quarter foundation magazine – Operations and products" (PDF). Hanson.biz. 31 May 2011. Archived from the original (PDF) on 30 May 2008. Retrieved 31 December 2011.
- ^ "One More Link to the West". New Scientist: 772. 25 March 1965.
- ^ Thornes, John Edward (1984). The Prediction of Ice Formation on Motorways in Britain (PDF) (Ph. D.). University College London. Retrieved 1 November 2015.
- ^ "This Sceptred Isle". Notes and Queries. Guardian. Retrieved 14 February 2016.
- ^ "Council will look again at case for M-way link". icwales. 23 June 2007.
- ^ "Business park plan 'would hit green land'". icwales. 19 December 2007.
- ^ Salmon, Jeff (11 October 2010). "M4 J31 Freedom of information act". www.whatdotheyknow.com. Retrieved 3 January 2016.
- ^ "M4 Exit List". CBRD. Archived from the original on 25 January 2016. Retrieved 14 February 2016.
- ^ "The M4 Motorway (Junction 41, Westbound Exit Slip Road, Sunnycroft Roundabout, Baglan, Neath Port Talbot) (50 MPH Speed Limit) Regulations 2010" (PDF). Assembly for Wales. Retrieved 14 February 2016.
- ^ "Are M4 plans on the right track?". South Wales Evening Post. 12 December 2007.
- ^ "Twice-a-day trial closure of Port Talbot M4 junction starts". BBC News. 4 August 2014.
- Wales Online. 4 August 2014.
- ^ "200 attend meeting over M4 junction 41 Port Talbot closure". BBC News. 12 March 2015.
- ^ "M4 Port Talbot junction 41 trial closures end". BBC News. 29 May 2015.
- Wales Online. 29 May 2015.
- ^ "M4 relief road: Proposals cost £114m before scheme was axed". BBC News. 5 June 2019.
- ^ "Plans for the M4 Toll (Newport)". BBC News. 20 September 2007. Retrieved 12 May 2010.
- ^ M4 corridor enhancement measures: Overview. Accessed 5 March 2012
- ^ "The New M4 Project – Magor to Castleton". Welsh Assembly Government. 13 July 2009.
- ^ Area 3 Driver Location Signs (map) – Highway Authority, 2009
- ^ Driver Location Signs, M5 J18-11, M4 J22-15 (map) Highway Authority 2009
- ^ "Traffic England Live Traffic Condition Map (selected Popups)". Highways Agency. Archived from the original on 10 February 2012. Retrieved 5 November 2009.
- ^ "Resources". Traffig Cymru/Traffic Wales. Archived from the original on 3 September 2011. Retrieved 22 August 2011.
Select Telephone & marker post locations.
- ^ a b "Road death toll mounts". The Daily Telegraph. London. 10 July 2003. Archived from the original on 12 January 2022.
- ^ Holt, Gerry (6 November 2011). "M5 motorway crash: How safe are Britain's motorways?". BBC News. Retrieved 4 June 2020.
- ^ "Record producer dies in crash". BBC News Online. 22 July 2002. Retrieved 13 February 2015.
Further reading
- Jackson, Mike (2005). The M4 Sights Guide. Severnpix. ISBN 978-0954540227.
External links
Geographic data related to M4 motorway at OpenStreetMap