M4 Traffic News
The M4 is a motorway that runs from London, all the way to south Wales, stretching across the west of the UK. It opened in 1961 and was completed in 1996. The M4 carries over 130,000 vehicles every day, according to data from National Highways.
The starting point for it is Chiswick, and it ends at Pont Abraham in Carmarthenshire. The full length of the M4 motorway is 189 miles, and M4 traffic passes several major cities and towns along the route, including Reading, Bristol, Cardiff and Swansea. It also runs past Heathrow Airport, providing access to all five terminals via Junction 3 and Junction 4B. The area of the UK that runs alongside the M4 is often referred to as the M4 corridor.
There are several notable sections on the M4. It has two four-level stack interchanges - at Junction 20 and Junction 4B - which is a key feature considering there are only three in the UK. The M4 is also one of only three motorways in Wales. There’s a toll bridge on the M4 that crosses the River Severn; drivers pay the toll to enter Wales but not to enter England.
Worst Junctions on the M4
As you’d expect from one of the UK’s busiest motorways, there are junctions on the M4 that may cause problems - do check M4 travel news and M4 traffic updates before starting your journey to avoid delays. These junctions can be congested:
Junction 20
Known as the Almondsbury Interchange, this junction near Bristol is one of the four-level stack interchanges noted above. When traffic is heavy, it gets extremely busy as this also connects to the M5. There are only two lanes to handle M5 traffic - it’s best to avoid this at peak times.
Junction 40 and 41
These junctions, in Port Talbot, have been problematic for years with tailbacks and speed cameras blighting motorists. It’s a major traffic congestion blackspot and there is an average speed camera system in place; with a 50mph limit in place it catches out plenty of drivers.
Junction 1
This is Chiswick roundabout, one of the oldest motorway junctions in the UK. It’s a meeting point for the north and south circular roads coming in and out of London so traffic can be very slow at times.
Junctions 25A and 26
There is frequently heavy congestion in this area around Newport, with a two-lane section at Brynglas Tunnels.
Accident Hotspots on the M4
Before driving on the M4, always look up M4 traffic updates to be aware of any road traffic accidents that may have occurred, and take steps to avoid the aftermath of incidents. Although motorways generally have a good safety record, accidents can happen at any junction.
Upcoming M4 Major Roadworks
Be aware of the impact major road works could have on M4 traffic and consult M4 travel news before and during any journey to try to minimise disruption.
For up-to-date information about upcoming roadworks on the M4, please visit the National Highways website, or look up a specific postcode on the local council website.