The M40 is the motorway that links the UK’s two biggest cities - London and Birmingham. It spans 89 miles in length, starting at Uxbridge - which is Junction 1 - and ending at Junction 17, Birmingham.
The route takes M40 traffic past a number of major UK cities, and connects to other key motorways. Junction 1a connects to the M1 via Watford, Heathrow Airport via the M4, and the M25, the London circular and the UK’s busiest motorway. Motorists using the M40 can also reach High Wycombe, Oxford - connecting to the A40 - Bicester, Northampton and Warwick.
Once the M40 reaches junction 17 it becomes the M42, and motorists can drive on to Birmingham and further north by taking the M6, or towards the south west on the M5.
The M40 marked its 50th anniversary in 2017 - the first section of the motorway opened in 1967.
Worst Junctions on the M40
Make use of our road planner to receive M40 traffic updates and M40 travel news. These updates can inform drivers of busy junctions and tailbacks. Junctions on the M40 that are typically regularly busy include:
This is the junction that handles M40 traffic as it takes the exit into High Wycombe and connects to the A404. Traffic lights don’t help vehicle flow, so it gets congested here.
Junctions 1 to 1a
Primarily down to the location of these two junctions, M40 traffic is particularly heavy here. This stretch of road begins in the west of London and then meets traffic all potentially heading for other major motorways in the shape of the M1, M11, M4 and M25, as well as Heathrow and Gatwick airport traffic.
Accident Hotspots on the M40
Accident hotspots are difficult to pinpoint because accidents can occur at anytime, and for several reasons. As always, best driving advice is to drive with caution, take regular breaks, and receive M40 traffic updates and travel news to be aware of any accidents and avoid resulting delays.
Junction 10 of the M40, between Oxford and Northampton, has been the scene for several accidents in recent years despite the creation of a new layout. Junction 5 of the M40 is also considered an accident hotspot, as is the stretch of motorway between junctions three and four.
Upcoming M40 Major Roadworks
Always consider roadworks causing delays and increasing journey times when you’re travelling on the M40. Some roadworks are in place quickly and don’t last long - make sure you look up traffic news for the M40 to check on these - while others are major projects that could be in place for months or even longer.
Upcoming major roadworks on the M40 include:
Junctions 3 to 8 - a noise barrier scheme has been underway on this stretch of the road since October 2017, with a completion date in spring 2018. This is resurfacing work.
Junction 16 - a major scheme, these roadworks will improve the M40 and M42 interchange, turning the area into a smart motorway with ‘all lane running’. The aim is to reduce congestion and improve safety. Work is expected to start by March 2020 with an end date to be confirmed.