The A400: where people are seriously hurt
Over 2021–2025, 91 people were killed or seriously injured in 86 collisions on the A400, making it the 150th worst numbered road in Britain by that measure.
86
serious or fatal collisions
91
people killed or seriously injured
2
collisions that took a life
#150
of 150 numbered roads
What the record shows
The A400 carries 511 recorded injury collisions over the period, 86 of them serious or fatal. Serious injury concentrates in Camden, Westminster, Islington. Collisions here are less likely than average to be fatal (2% against 7%), typical of lower-speed urban sections. Most collisions were recorded on 20 mph sections. The worst year of the period was 2022 with 20 serious collisions, and the count is flat between 2021 and 2025.
Every serious and fatal collision on the A400
Blue markers are serious collisions, red crosses fatal. Click any marker for the year. Zoom in to see the specific junctions and stretches where they cluster.
Where along the route
- Camden64 KSI
- Westminster17 KSI
- Islington5 KSI
Local authority areas with the most serious collisions on this road.
The trend
Serious and fatal collisions on the A400
2025: 18 (up 38.5% on the year before) · peak 20 in 2022 · 0% across the period
Axis clipped to the data range to show year-on-year movement.
About the A400
How many accidents happen on the A400?
Police recorded 511 injury collisions on the A400 over 2021–2025, of which 86 were fatal or serious. Those serious collisions left 91 people killed or seriously injured, including 2 fatal collisions.
Is the A400 a dangerous road?
By volume of serious injury it ranks 150 of the 150 numbered roads we analyse, and 139 among a roads. That is a count rather than a rate: longer and busier roads accumulate more collisions, so a high ranking reflects exposure as well as risk.
Where on the A400 do collisions happen?
They concentrate in Camden, Westminster, Islington. The map on this page plots every serious and fatal collision recorded on the route, so you can see the specific stretches rather than the total.
Counts include every collision the police recorded on this road number across all authority areas. They are not adjusted for traffic volume or road length, so treat them as a measure of where injury concentrates rather than a per-mile risk rating. Method. Free to reuse with attribution to this page.
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