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CrashStats

A4 accidents: crash map and statistics

Police recorded 51,606 collisions on the A4 from 1979 to 2025, with 64,372 casualties. Of those crashes, 761 were fatal and 8,308 serious, and 801 people were killed.

In 2025 there were 532 collisions on the A4, up 12% from 474 in 2024, with 648 casualties.

Live A4 closures, incidents and roadworks are checked every 5 minutes.

Collisions since 1979
51,606
2nd highest of 4,923 roads
Casualties
64,372
1.25 per collision
Fatal collisions
761
801 people killed
Serious collisions
8,308
9,360 seriously injured
Collisions in 2025
532
Up 12% on 2024
Casualties in 2025
648
Up 15% on 2024

Crash severity on the A4

On the A4, 1.5% of collisions were fatal and 16% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal7611.5%
  • Serious8,30816%
  • Slight42,53782%

Where the A4 ranks among 4,923 roads

Most collisions
2nd
Most casualties
6th
Most fatal collisions
12th
Most serious collisions
5th

A4 accidents by year

Collisions on the A4 peaked at 1,756 in 1984 and were down to 532 in 2025.

Collisions and casualties on the A4, 1979 to 2025

  • Collisions
  • Collisions in 2025: 532
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
2025532648
2024474565
2023524637
2022567689
2021500593
2020400470
2019601728
2018619761
2017705906
2016718898
2015749949
2014742926
2013759953
20128011,043
20118571,078
20108121,007
20097941,006
2008800995
20079211,163
20069191,155
20059621,187
20049631,188
20031,0931,372
20021,1671,439
20011,2521,639
20001,3041,618
19991,2921,634
19981,3021,663
19971,2811,618
19961,2661,575
19951,2321,499
19941,2621,602
19931,1981,520
19921,1231,411
19911,2511,571
19901,5051,880
19891,7082,106
19881,6252,058
19871,5992,014
19861,6201,995
19851,6822,098
19841,7562,171
19831,6211,953
19821,6662,025
19811,6702,045
19801,6822,123
19791,7302,198

When crashes happen on the A4

Friday has the most collisions on the A4 (8,829), and 3pm to 6pm is the busiest time of day (11,463).

Collisions by day of the week

  • Monday7,160 (14%)
  • Tuesday7,612 (15%)
  • Wednesday7,954 (15%)
  • Thursday8,120 (16%)
  • Friday8,829 (17%)
  • Saturday6,721 (13%)
  • Sunday5,210 (10%)

Collisions by time of day

  • Midnight to 3am2,548 (4.9%)
  • 3am to 6am1,312 (2.5%)
  • 6am to 9am6,390 (12%)
  • 9am to noon7,379 (14%)
  • Noon to 3pm8,859 (17%)
  • 3pm to 6pm11,463 (22%)
  • 6pm to 9pm8,104 (16%)
  • 9pm to midnight5,551 (11%)

Collisions by month

  • January3,953 (7.7%)
  • February3,755 (7.3%)
  • March4,108 (8%)
  • April3,952 (7.7%)
  • May4,338 (8.4%)
  • June4,448 (8.6%)
  • July4,671 (9.1%)
  • August4,339 (8.4%)
  • September4,479 (8.7%)
  • October4,786 (9.3%)
  • November4,622 (9%)
  • December4,155 (8.1%)

Light conditions at the time

  • Daylight35,337 (68%)
  • Dark, street lights lit14,954 (29%)
  • Dark, no street lighting637 (1.2%)
  • Dark, lighting unknown441 (0.9%)
  • Dark, street lights unlit230 (0.4%)
  • Not recorded7 (under 0.1%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in A4 crashes

On the A4, 60% of collisions happened where the speed limit was 30 mph and 75% on a dry road surface.

Speed limit at the scene

  • 20 mph930 (1.8%)
  • 30 mph31,066 (60%)
  • 40 mph12,543 (24%)
  • 50 mph1,458 (2.8%)
  • 60 mph4,644 (9%)
  • 70 mph918 (1.8%)
  • Not recorded47 (0.1%)

Weather at the time

  • Fine, no high winds40,438 (78%)
  • Raining, no high winds6,023 (12%)
  • Fine with high winds469 (0.9%)
  • Raining with high winds418 (0.8%)
  • Other3,579 (6.9%)
  • Not recorded679 (1.3%)

Road surface

  • Dry38,699 (75%)
  • Wet or damp12,136 (24%)
  • Frost or ice379 (0.7%)
  • Snow147 (0.3%)
  • Other54 (0.1%)
  • Not recorded191 (0.4%)

Type of road

  • Single carriageway23,189 (45%)
  • Dual carriageway17,036 (33%)
  • One way street or slip road5,335 (10%)
  • Roundabout5,258 (10%)
  • Not recorded788 (1.5%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in A4 crashes

Car occupants make up 47% of the people killed or injured on the A4, followed by motorcyclists (18%).

Casualties by road user

  • Car occupant30,350 (47%)
  • Motorcyclist11,329 (18%)
  • Pedestrian10,275 (16%)
  • Cyclist6,059 (9.4%)
  • Bus or coach occupant2,885 (4.5%)
  • Taxi or private hire car occupant1,564 (2.4%)
  • Other1,872 (2.9%)
  • Not recorded38 (0.1%)

Vehicles involved

  • Car59,490 (63%)
  • Motorcycle12,408 (13%)
  • Pedal cycle6,298 (6.7%)
  • Van or goods vehicle up to 3.5 tonnes4,327 (4.6%)
  • Bus or coach4,204 (4.5%)
  • Taxi or private hire car3,710 (4%)
  • Other3,375 (3.6%)
  • Not recorded52 (0.1%)

Casualties by age

  • 0 to 5701 (1.1%)
  • 6 to 101,008 (1.6%)
  • 11 to 151,887 (2.9%)
  • 16 to 208,926 (14%)
  • 21 to 259,953 (15%)
  • 26 to 3515,291 (24%)
  • 36 to 459,538 (15%)
  • 46 to 556,581 (10%)
  • 56 to 654,014 (6.2%)
  • 66 to 752,099 (3.3%)
  • Over 751,299 (2%)
  • Not recorded3,075 (4.8%)

Drivers, passengers and pedestrians

  • Driver or rider39,062 (61%)
  • Passenger15,035 (23%)
  • Pedestrian10,275 (16%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the A4

Map of the 25 most recent crashes on the A4

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

  • 25 crashes
  • Fatal
  • Serious
  • Slight

A4 crashes by council area

Collisions on the A4 were recorded in 16 council areas. Westminster has the most, with 10,726, followed by Hounslow (7,381) and Kensington and Chelsea (4,862).

Collisions on the A4 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stWestminster10,72611,968611,526
2ndHounslow7,3819,5791211,058
3rdKensington and Chelsea4,8625,69055784
4thSlough4,6636,07150644
5thBristol3,8814,78983610
6thWest Berkshire3,6424,90096762
7thWiltshire3,2544,54195660
8thBath and North East Somerset2,4163,05636508
9thReading2,3363,00422367
10thHammersmith and Fulham2,0392,58163375
11thHillingdon1,8592,51020311
12thWindsor and Maidenhead1,5671,90817227
13thWokingham1,1811,54931205
14thCity of London8639571103
15thBuckinghamshire7651,0167144
16thHeathrow Airport406413

A4 crashes by town

Collisions on the A4 were recorded in 32 towns and built-up areas, led by City of Westminster (10,125) and Hounslow (6,446).

Recent crashes on the A4

These are the 25 most recent collisions on the A4, from 17 December to 31 December 2025.

Severity