The A420: where people are seriously hurt
Over 2021–2025, 140 people were killed or seriously injured in 124 collisions on the A420, making it the 93th worst numbered road in Britain by that measure.
124
serious or fatal collisions
140
people killed or seriously injured
7
collisions that took a life
#93
of 150 numbered roads
What the record shows
The A420 carries 683 recorded injury collisions over the period, 124 of them serious or fatal. Serious injury concentrates in Oxford, Vale of White Horse, Wiltshire, with 3 further areas also recording collisions. Its fatal share, 6%, sits close to the 7% average for the numbered network. Most collisions were recorded on 20 mph sections. The worst year of the period was 2025 with 32 serious collisions, and the count is up 39% between 2021 and 2025.
Every serious and fatal collision on the A420
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
- Oxford47 KSI
- Vale of White Horse34 KSI
- Wiltshire17 KSI
- Bristol, City of15 KSI
- South Gloucestershire10 KSI
- Swindon1 KSI
Local authority areas with the most serious collisions on this road.
The trend
Serious and fatal collisions on the A420
2025: 32 (up 18.5% on the year before) · peak 32 in 2025 · +39.1% across the period
Axis clipped to the data range to show year-on-year movement.
About the A420
How many accidents happen on the A420?
Police recorded 683 injury collisions on the A420 over 2021–2025, of which 124 were fatal or serious. Those serious collisions left 140 people killed or seriously injured, including 7 fatal collisions.
Is the A420 a dangerous road?
By volume of serious injury it ranks 93 of the 150 numbered roads we analyse, and 86 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 A420 do collisions happen?
They concentrate in Oxford, Vale of White Horse, Wiltshire. 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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