Junction 15 of the M5 is the Almondsbury Interchange, on the northern edge of Bristol, where the M5 and the M4 cross. When it opened in 1966 it was the first four-level interchange in Britain. The stretch from there to Junction 16 (A38, Aztec West and Filton) carried 129,400 vehicles a day in the Department for Transport’s 2025 counts, the third busiest stretch of the M5 and the busiest south of Worcestershire. This page covers M5 Junction 15 to 16 traffic.

Latest M5 traffic news around Almondsbury

For all the news currently reported on the M5, see our latest M5 traffic news. If your journey continues onto the M4, check M4 Traffic as well.

How busy is the M5 between Junction 15 and 16?

129,400 vehicles a day is an average of about 5,392 vehicles every hour, or around 90 a minute, spread across the full 24 hours. The real flow rises and falls sharply through the day, so the peaks are much heavier than that average.

A large share of this traffic is moving between two motorways. Drivers heading from the Midlands to South Wales or London leave the M5 here, and traffic from the M4 joins it for Bristol and the South West.

What is on the road at J15 to J16

Cars and taxis are about 75% of the traffic, some 97,396 a day. There are 10,610 lorries a day, around 8.2% of everything using the stretch, and roughly 21,394 other vehicles, most of them vans.

Because Almondsbury links two of the busiest motorways in the South West, trouble on either road can be felt here. A closure on the M4 near the interchange can push traffic onto the M5, and the other way round, so check M5 accidents and M5 roadworks before you leave.

One interchange, two junction numbers

The Almondsbury Interchange has a different number on each motorway. It is Junction 15 on the M5 and Junction 20 on the M4, and the Department for Transport records it as 15/20. So if you hear about trouble at “M4 Junction 20”, it is the same place. Variable speed limits are used on the M5 around the interchange, so the limit can be lower than 70 mph when the road is busy or there is a problem ahead. Our M5 speed signs page shows the limits currently set.

Around Junction 15 and 16

Junction 16 is the A38, serving Aztec West and Filton. Just beyond it is Junction 17 for Cribbs Causeway, and that stretch is the fourth busiest on the M5. North of Almondsbury the M5 heads towards Junction 14 at Thornbury and Falfield.

The nearest services are Michaelwood Services, between Junctions 13 and 14 to the north, and Gordano Services at Junction 19 to the south. Our map of the M5 junctions shows the full route.

Where J15 to J16 ranks on the M5

The table shows the six busiest stretches of the M5. Two of the top four are here on the northern edge of Bristol, one each side of Junction 16.

Rank	M5 stretch	Vehicles per day	Cars & taxis	Lorries
1	J5 to J6	150,612	108,634	15,176
2	J4a to J5	136,816	99,318	13,457
3	J15 to J16	129,400	97,396	10,610
4	J16 to J17	121,685	90,630	9,618
5	J1 to J2	119,998	83,626	11,454
6	J20 to J21	118,811	92,064	7,702

Traffic figures are annual average daily flows, both directions together, from the Department for Transport road traffic statistics for 2025. The DfT measures the M5 at 55 count points; the ranking uses the 24 stretches that run between numbered junctions. Where a stretch has more than one count point, the busiest measured point is shown. Hourly and per-minute figures are simple averages across the whole day and night, not peak-time figures. Contains public sector information licensed under the Open Government Licence v3.0.