Which UK Motorway Has the Most Accidents? M25, M1, M6, M4, M62 and M5 Compared

Quick answer: Of Britain's six busiest long-distance motorways, the M25 records the most injury collisions: 2,302 police-reported collisions from 2021 to 2025, ahead of the M1 (1,929) and the M6 (1,823). But the M25 is not where the most people die. The M6 recorded the most fatal collisions (56) and the most deaths (64), followed by the M1 with 49 fatal collisions and 54 deaths. The M25 had just 25 fatal collisions, the lowest share of any of the six: about 1 in every 92 of its collisions was fatal, against roughly 1 in 32 on the M4, M5 and M6. These figures come from the Department for Transport's STATS19 data, which counts collisions in which at least one person was injured, and they measure recorded crashes, not how risky each motorway is per journey.

The six motorways compared (2021–2025)

• M25: 2,302 collisions, 25 fatal, 344 serious, 29 people killed
• M1: 1,929 collisions, 49 fatal, 306 serious, 54 people killed
• M6: 1,823 collisions, 56 fatal, 344 serious, 64 people killed
• M4: 1,152 collisions, 36 fatal, 171 serious, 40 people killed
• M62: 963 collisions, 26 fatal, 203 serious, 28 people killed
• M5: 800 collisions, 25 fatal, 163 serious, 27 people killed

Together the six recorded 8,969 injury collisions and 242 deaths in five years. Every figure links back to a full page with yearly tables, maps and CSV downloads: M25, M1, M6, M4, M62 and M5.

Why the M25 has the most collisions but the fewest deaths

The M25 is only about 117 miles long, yet it carries some of the heaviest traffic in Europe. Divided by length, it recorded roughly 20 injury collisions per mile over five years, about twice the M1 (10 per mile on about 193 miles) and four times the M5 (5 per mile on about 163 miles).

Congestion helps explain both halves of that picture. Queuing, stop-start traffic produces many shunts and lane-change collisions, which is why 1,933 of the M25's collisions were classed as slight. Slower traffic also means less energy in each impact, and the energy of a crash rises with the square of speed (see the physics of crash survival). The motorways with fewer collisions per mile show the opposite pattern: on the M4, M5 and M6 about 3% of collisions were fatal, nearly three times the M25's share.

When motorway collisions happen

The pattern is strikingly consistent. On all six motorways Friday was the day with the most recorded collisions, and the busiest hour was 5pm (4pm on the M6), the evening peak. The busiest month fell late in the year on five of the six: October on the M6, M25 and M62, November on the M4 and December on the M1. The M5 was the exception, peaking in August, the holiday month for traffic to the South West. Between 12% and 16% of collisions happened between 10pm and 6am, when traffic is much lighter.

Speed limits tell the same story from a different angle. Most collisions happened where the limit was 70 mph, but hundreds happened in 40 and 50 mph limits, which on motorways normally means roadworks or managed sections. On the M4, 161 collisions were recorded in 50 mph limits.

Where on each motorway

STATS19 records the council area of every collision, which shows where the numbers concentrate:

• M25: Runnymede (235), Epping Forest (196) and Sevenoaks (185)
• M1: Central Bedfordshire (308), St Albans (229) and West Northamptonshire (197)
• M6: Cheshire East (198), Westmorland and Furness (158) and Walsall (145)
• M4: Hillingdon (157), West Berkshire (134) and South Gloucestershire (101)
• M62: Kirklees (199), Leeds (171) and Calderdale (151), including the trans-Pennine stretch
• M5: Somerset (99), North Somerset (95) and Tewkesbury (75)

To see these hotspots on a map, use the historical accident hotspots explorer, which covers all 350 local authorities, or plot a whole journey with the route accident history tool.

Who gets hurt

Car occupants make up the vast majority of casualties on every motorway. Motorcyclists are a small share but stand out on the M25 (127 casualties) and the M6 (76). Pedestrian casualties are rare but real: 31 on the M1 and 30 on the M6, often after a breakdown or an earlier crash. If you break down, get out on the side away from traffic, stand behind the barrier and call for help.

Is traffic making them more dangerous?

The counts move less than headlines suggest. The M25 peaked at 504 collisions in 2023 and fell to 420 in 2024. The M6 rose from 331 in 2023 to 402 in 2025, and recorded 16 fatal collisions in 2022 and 14 in 2025. Year-to-year changes can reflect traffic growth, long roadworks or police forces switching to the CRASH recording system, not only real changes in safety, so treat a single year with caution. Our guide to reading accident statistics without being fooled explains why.

How these numbers were counted

The data is the Department for Transport's road safety open data (STATS19) for 2021 to 2025, published under the Open Government Licence. A collision counts for a motorway when police record that motorway as the first road involved; slip roads recorded as another road, and collisions where the motorway is only the second road, are not included. Damage-only crashes are not in STATS19. Motorway lengths are approximate, so the per-mile figures are a rough guide, and none of these numbers account for how many vehicles use each road. For every UK council's figures, see UK road accidents by local authority, and download the underlying tables from the data page.