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CrashStats

A421 accidents: crash map and statistics

Police recorded 5,542 collisions on the A421 from 1979 to 2025, with 8,500 casualties. Of those crashes, 181 were fatal and 856 serious, and 204 people were killed.

In 2025 there were 59 collisions on the A421, down 23% from 77 in 2024, with 78 casualties.

Live A421 closures, incidents and roadworks are checked every 5 minutes.

Collisions since 1979
5,542
180th highest of 4,923 roads
Casualties
8,500
1.53 per collision
Fatal collisions
181
204 people killed
Serious collisions
856
1,139 seriously injured
Collisions in 2025
59
Down 23% on 2024
Casualties in 2025
78
Down 30% on 2024

Crash severity on the A421

On the A421, 3.3% of collisions were fatal and 15% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal1813.3%
  • Serious85615%
  • Slight4,50581%

Where the A421 ranks among 4,923 roads

Most collisions
180th
Most casualties
160th
Most fatal collisions
109th
Most serious collisions
221st

A421 accidents by year

Collisions on the A421 peaked at 202 in 1997 and were down to 59 in 2025.

Collisions and casualties on the A421, 1979 to 2025

  • Collisions
  • Collisions in 2025: 59
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
20255978
202477112
20236287
202273103
202171123
20206892
2019102147
201891132
2017108183
2016108164
2015115183
2014117175
2013112155
2012118168
2011108160
2010101145
2009114188
2008126213
2007154245
2006135204
2005139250
2004177260
2003125178
2002157245
2001187301
2000177265
1999162253
1998192296
1997202318
1996151226
1995131216
1994149239
1993110176
1992136215
1991108164
1990133223
1989131196
1988127195
1987125189
1986130195
1985107161
198492141
198383121
198270100
19817495
19806199
197987126

When crashes happen on the A421

Friday has the most collisions on the A421 (923), and 3pm to 6pm is the busiest time of day (1,274).

Collisions by day of the week

  • Monday810 (15%)
  • Tuesday805 (15%)
  • Wednesday791 (14%)
  • Thursday803 (14%)
  • Friday923 (17%)
  • Saturday745 (13%)
  • Sunday665 (12%)

Collisions by time of day

  • Midnight to 3am191 (3.4%)
  • 3am to 6am142 (2.6%)
  • 6am to 9am877 (16%)
  • 9am to noon803 (14%)
  • Noon to 3pm915 (17%)
  • 3pm to 6pm1,274 (23%)
  • 6pm to 9pm879 (16%)
  • 9pm to midnight461 (8.3%)

Collisions by month

  • January438 (7.9%)
  • February399 (7.2%)
  • March460 (8.3%)
  • April436 (7.9%)
  • May464 (8.4%)
  • June445 (8%)
  • July429 (7.7%)
  • August479 (8.6%)
  • September468 (8.4%)
  • October500 (9%)
  • November528 (9.5%)
  • December496 (8.9%)

Light conditions at the time

  • Daylight3,897 (70%)
  • Dark, street lights lit895 (16%)
  • Dark, no street lighting647 (12%)
  • Dark, lighting unknown77 (1.4%)
  • Dark, street lights unlit22 (0.4%)
  • Not recorded4 (0.1%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in A421 crashes

On the A421, 53% of collisions happened where the speed limit was 60 mph and 64% on a dry road surface.

Speed limit at the scene

  • 20 mph1 (under 0.1%)
  • 30 mph520 (9.4%)
  • 40 mph173 (3.1%)
  • 50 mph77 (1.4%)
  • 60 mph2,923 (53%)
  • 70 mph1,847 (33%)
  • Not recorded1 (under 0.1%)

Weather at the time

  • Fine, no high winds4,366 (79%)
  • Raining, no high winds667 (12%)
  • Fine with high winds113 (2%)
  • Fog or mist100 (1.8%)
  • Other248 (4.5%)
  • Not recorded48 (0.9%)

Road surface

  • Dry3,564 (64%)
  • Wet or damp1,777 (32%)
  • Frost or ice128 (2.3%)
  • Snow28 (0.5%)
  • Other14 (0.3%)
  • Not recorded31 (0.6%)

Type of road

  • Single carriageway2,816 (51%)
  • Dual carriageway1,541 (28%)
  • Roundabout1,042 (19%)
  • One way street or slip road134 (2.4%)
  • Not recorded9 (0.2%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in A421 crashes

Car occupants make up 76% of the people killed or injured on the A421, followed by motorcyclists (9.3%).

Casualties by road user

  • Car occupant6,459 (76%)
  • Motorcyclist789 (9.3%)
  • Van occupant373 (4.4%)
  • Goods vehicle occupant (over 3.5 tonnes)268 (3.2%)
  • Pedestrian221 (2.6%)
  • Cyclist201 (2.4%)
  • Other188 (2.2%)
  • Not recorded1 (under 0.1%)

Vehicles involved

  • Car8,516 (74%)
  • Goods vehicle over 3.5 tonnes948 (8.3%)
  • Motorcycle784 (6.8%)
  • Van or goods vehicle up to 3.5 tonnes710 (6.2%)
  • Pedal cycle208 (1.8%)
  • Other vehicle82 (0.7%)
  • Other221 (1.9%)
  • Not recorded17 (0.1%)

Casualties by age

  • 0 to 5131 (1.5%)
  • 6 to 10184 (2.2%)
  • 11 to 15246 (2.9%)
  • 16 to 201,152 (14%)
  • 21 to 251,176 (14%)
  • 26 to 352,003 (24%)
  • 36 to 451,450 (17%)
  • 46 to 551,049 (12%)
  • 56 to 65543 (6.4%)
  • 66 to 75289 (3.4%)
  • Over 75128 (1.5%)
  • Not recorded149 (1.8%)

Drivers, passengers and pedestrians

  • Driver or rider5,822 (68%)
  • Passenger2,457 (29%)
  • Pedestrian221 (2.6%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the A421

Map of the 25 most recent crashes on the A421

Use the arrow keys to move the map and the plus and minus keys to zoom.

  • 25 crashes
  • Serious
  • Slight

A421 crashes by council area

Collisions on the A421 were recorded in 6 council areas. Milton Keynes has the most, with 1,903, followed by Bedford (1,007) and Buckinghamshire (989).

Collisions on the A421 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stMilton Keynes1,9032,71137229
2ndBedford1,0071,58033154
3rdBuckinghamshire9891,58440200
4thCentral Bedfordshire9401,55340144
5thCherwell6831,04030122
6thWest Northamptonshire172817

A421 crashes by town

Collisions on the A421 were recorded in 9 towns and built-up areas, led by Bicester (274) and Bletchley (120).

Recent crashes on the A421

These are the 25 most recent collisions on the A421, from 22 August to 19 December 2025.

Severity