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CrashStats

A4020 accidents: crash map and statistics

Police recorded 19,356 collisions on the A4020 from 1979 to 2025, with 23,128 casualties. Of those crashes, 169 were fatal and 2,864 serious, and 172 people were killed.

In 2025 there were 216 collisions on the A4020, up 1% from 213 in 2024, with 242 casualties.

Collisions since 1979
19,356
36th highest of 4,923 roads
Casualties
23,128
1.19 per collision
Fatal collisions
169
172 people killed
Serious collisions
2,864
3,095 seriously injured
Collisions in 2025
216
Up 1% on 2024
Casualties in 2025
242
Up 1% on 2024

Crash severity on the A4020

On the A4020, 0.9% of collisions were fatal and 15% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal1690.9%
  • Serious2,86415%
  • Slight16,32384%

Where the A4020 ranks among 4,923 roads

Most collisions
36th
Most casualties
43rd
Most fatal collisions
117th
Most serious collisions
44th

A4020 accidents by year

Collisions on the A4020 peaked at 625 in 1984 and were down to 216 in 2025.

Collisions and casualties on the A4020, 1979 to 2025

  • Collisions
  • Collisions in 2025: 216
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
2025216242
2024213239
2023240266
2022267300
2021236272
2020230271
2019280336
2018277342
2017317394
2016306359
2015310372
2014274331
2013303351
2012300379
2011319382
2010348419
2009316370
2008276320
2007294363
2006314384
2005349435
2004393458
2003452551
2002469587
2001504592
2000527631
1999450554
1998455539
1997526620
1996519627
1995452536
1994534671
1993516629
1992506615
1991518597
1990552649
1989574677
1988514634
1987491595
1986533645
1985549660
1984625720
1983600706
1982559669
1981556681
1980499592
1979498566

When crashes happen on the A4020

Friday has the most collisions on the A4020 (3,226), and 3pm to 6pm is the busiest time of day (4,387).

Collisions by day of the week

  • Monday2,724 (14%)
  • Tuesday2,847 (15%)
  • Wednesday2,802 (14%)
  • Thursday2,986 (15%)
  • Friday3,226 (17%)
  • Saturday2,767 (14%)
  • Sunday2,004 (10%)

Collisions by time of day

  • Midnight to 3am882 (4.6%)
  • 3am to 6am293 (1.5%)
  • 6am to 9am2,003 (10%)
  • 9am to noon2,619 (14%)
  • Noon to 3pm3,465 (18%)
  • 3pm to 6pm4,387 (23%)
  • 6pm to 9pm3,421 (18%)
  • 9pm to midnight2,286 (12%)

Collisions by month

  • January1,480 (7.6%)
  • February1,370 (7.1%)
  • March1,560 (8.1%)
  • April1,551 (8%)
  • May1,658 (8.6%)
  • June1,683 (8.7%)
  • July1,643 (8.5%)
  • August1,573 (8.1%)
  • September1,678 (8.7%)
  • October1,821 (9.4%)
  • November1,791 (9.3%)
  • December1,548 (8%)

Light conditions at the time

  • Daylight13,089 (68%)
  • Dark, street lights lit6,061 (31%)
  • Dark, lighting unknown135 (0.7%)
  • Dark, street lights unlit46 (0.2%)
  • Dark, no street lighting25 (0.1%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in A4020 crashes

On the A4020, 74% of collisions happened where the speed limit was 30 mph and 77% on a dry road surface.

Speed limit at the scene

  • 20 mph1,072 (5.5%)
  • 30 mph14,377 (74%)
  • 40 mph3,729 (19%)
  • 50 mph58 (0.3%)
  • 60 mph106 (0.5%)
  • 70 mph12 (0.1%)
  • Not recorded2 (under 0.1%)

Weather at the time

  • Fine, no high winds15,003 (78%)
  • Raining, no high winds2,359 (12%)
  • Fine with high winds130 (0.7%)
  • Raining with high winds79 (0.4%)
  • Other1,596 (8.2%)
  • Not recorded189 (1%)

Road surface

  • Dry14,965 (77%)
  • Wet or damp4,133 (21%)
  • Frost or ice113 (0.6%)
  • Snow39 (0.2%)
  • Flood over 3cm deep4 (under 0.1%)
  • Not recorded102 (0.5%)

Type of road

  • Single carriageway12,042 (62%)
  • Dual carriageway5,754 (30%)
  • One way street or slip road435 (2.2%)
  • Roundabout361 (1.9%)
  • Not recorded764 (3.9%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in A4020 crashes

Car occupants make up 40% of the people killed or injured on the A4020, followed by pedestrians (23%).

Casualties by road user

  • Car occupant9,176 (40%)
  • Pedestrian5,271 (23%)
  • Motorcyclist3,433 (15%)
  • Cyclist2,875 (12%)
  • Bus or coach occupant1,644 (7.1%)
  • Van occupant354 (1.5%)
  • Other354 (1.5%)
  • Not recorded21 (0.1%)

Vehicles involved

  • Car21,474 (65%)
  • Motorcycle3,835 (12%)
  • Pedal cycle2,966 (9%)
  • Bus or coach2,051 (6.2%)
  • Van or goods vehicle up to 3.5 tonnes1,592 (4.8%)
  • Goods vehicle over 3.5 tonnes443 (1.3%)
  • Taxi or private hire car380 (1.2%)
  • Other284 (0.9%)

Casualties by age

  • 0 to 5403 (1.7%)
  • 6 to 10491 (2.1%)
  • 11 to 15933 (4%)
  • 16 to 203,064 (13%)
  • 21 to 253,533 (15%)
  • 26 to 355,317 (23%)
  • 36 to 453,001 (13%)
  • 46 to 552,109 (9.1%)
  • 56 to 651,335 (5.8%)
  • 66 to 75890 (3.8%)
  • Over 75615 (2.7%)
  • Not recorded1,437 (6.2%)

Drivers, passengers and pedestrians

  • Driver or rider12,530 (54%)
  • Passenger5,327 (23%)
  • Pedestrian5,271 (23%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the A4020

Map of the 25 most recent crashes on the A4020

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

  • 25 crashes
  • Serious
  • Slight

A4020 crashes by council area

Collisions on the A4020 were recorded in 5 council areas. Ealing has the most, with 11,409, followed by Hillingdon (5,013) and Hammersmith and Fulham (2,642).

Collisions on the A4020 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stEaling11,40913,428911,649
2ndHillingdon5,0136,33657815
3rdHammersmith and Fulham2,6422,97113342
4thBuckinghamshire192254343
5thSouth Oxfordshire99138515

A4020 crashes by town

Collisions on the A4020 were recorded in 4 towns and built-up areas, led by Ealing (10,458) and Hillingdon (4,443).

Recent crashes on the A4020

These are the 25 most recent collisions on the A4020, from 17 November to 25 December 2025.

Severity