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CrashStats

A4140 accidents: crash map and statistics

Police recorded 2,719 collisions on the A4140 from 1979 to 2025, with 3,422 casualties. Of those crashes, 38 were fatal and 429 serious, and 39 people were killed.

In 2025 there were 36 collisions on the A4140, up 50% from 24 in 2024, with 45 casualties.

Collisions since 1979
2,719
428th highest of 4,923 roads
Casualties
3,422
1.26 per collision
Fatal collisions
38
39 people killed
Serious collisions
429
499 seriously injured
Collisions in 2025
36
Up 50% on 2024
Casualties in 2025
45
Up 29% on 2024

Crash severity on the A4140

On the A4140, 1.4% of collisions were fatal and 16% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal381.4%
  • Serious42916%
  • Slight2,25283%

Where the A4140 ranks among 4,923 roads

Most collisions
428th
Most casualties
468th
Most fatal collisions
552nd
Most serious collisions
499th

A4140 accidents by year

Collisions on the A4140 peaked at 87 in 1991 and were down to 36 in 2025.

Collisions and casualties on the A4140, 1979 to 2025

  • Collisions
  • Collisions in 2025: 36
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
20253645
20242435
20232840
20224662
20212934
20203238
20194550
20184052
20174655
20165563
20154661
20146479
20133347
20124254
20114350
20105365
20094052
20084049
20073949
20064553
20055766
20044658
20035871
20025486
20015575
20005783
199980102
19987689
19977891
19967086
19956672
19947594
19937085
19926373
199187105
19907098
19897392
19887891
19877795
19867485
19857994
19847288
19837196
198271100
198186102
19807199
197979113

When crashes happen on the A4140

Friday has the most collisions on the A4140 (455), and 3pm to 6pm is the busiest time of day (606).

Collisions by day of the week

  • Monday355 (13%)
  • Tuesday403 (15%)
  • Wednesday400 (15%)
  • Thursday389 (14%)
  • Friday455 (17%)
  • Saturday376 (14%)
  • Sunday341 (13%)

Collisions by time of day

  • Midnight to 3am87 (3.2%)
  • 3am to 6am37 (1.4%)
  • 6am to 9am346 (13%)
  • 9am to noon334 (12%)
  • Noon to 3pm466 (17%)
  • 3pm to 6pm606 (22%)
  • 6pm to 9pm515 (19%)
  • 9pm to midnight328 (12%)

Collisions by month

  • January248 (9.1%)
  • February200 (7.4%)
  • March210 (7.7%)
  • April201 (7.4%)
  • May216 (7.9%)
  • June232 (8.5%)
  • July236 (8.7%)
  • August218 (8%)
  • September229 (8.4%)
  • October241 (8.9%)
  • November264 (9.7%)
  • December224 (8.2%)

Light conditions at the time

  • Daylight1,838 (68%)
  • Dark, street lights lit848 (31%)
  • Dark, lighting unknown25 (0.9%)
  • Dark, street lights unlit5 (0.2%)
  • Dark, no street lighting3 (0.1%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in A4140 crashes

On the A4140, 82% of collisions happened where the speed limit was 30 mph and 72% on a dry road surface.

Speed limit at the scene

  • 20 mph14 (0.5%)
  • 30 mph2,235 (82%)
  • 40 mph386 (14%)
  • 50 mph64 (2.4%)
  • 60 mph12 (0.4%)
  • 70 mph8 (0.3%)

Weather at the time

  • Fine, no high winds2,036 (75%)
  • Raining, no high winds356 (13%)
  • Raining with high winds18 (0.7%)
  • Fine with high winds15 (0.6%)
  • Other249 (9.2%)
  • Not recorded45 (1.7%)

Road surface

  • Dry1,969 (72%)
  • Wet or damp697 (26%)
  • Frost or ice23 (0.8%)
  • Snow15 (0.6%)
  • Flood over 3cm deep1 (under 0.1%)
  • Not recorded14 (0.5%)

Type of road

  • Single carriageway1,867 (69%)
  • Dual carriageway419 (15%)
  • Roundabout203 (7.5%)
  • One way street or slip road50 (1.8%)
  • Not recorded180 (6.6%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in A4140 crashes

Car occupants make up 60% of the people killed or injured on the A4140, followed by pedestrians (15%).

Casualties by road user

  • Car occupant2,065 (60%)
  • Pedestrian528 (15%)
  • Motorcyclist421 (12%)
  • Cyclist203 (5.9%)
  • Van occupant90 (2.6%)
  • Bus or coach occupant81 (2.4%)
  • Other33 (1%)
  • Not recorded1 (under 0.1%)

Vehicles involved

  • Car3,858 (78%)
  • Motorcycle432 (8.7%)
  • Van or goods vehicle up to 3.5 tonnes255 (5.1%)
  • Pedal cycle205 (4.1%)
  • Bus or coach95 (1.9%)
  • Goods vehicle over 3.5 tonnes60 (1.2%)
  • Taxi or private hire car37 (0.7%)
  • Other32 (0.6%)

Casualties by age

  • 0 to 573 (2.1%)
  • 6 to 1083 (2.4%)
  • 11 to 15123 (3.6%)
  • 16 to 20464 (14%)
  • 21 to 25480 (14%)
  • 26 to 35685 (20%)
  • 36 to 45492 (14%)
  • 46 to 55326 (9.5%)
  • 56 to 65242 (7.1%)
  • 66 to 75139 (4.1%)
  • Over 75121 (3.5%)
  • Not recorded194 (5.7%)

Drivers, passengers and pedestrians

  • Driver or rider2,106 (62%)
  • Passenger788 (23%)
  • Pedestrian528 (15%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the A4140

Map of the 25 most recent crashes on the A4140

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

  • 25 crashes
  • Serious
  • Slight

A4140 crashes by council area

Collisions on the A4140 were recorded in 4 council areas. Harrow has the most, with 1,821, followed by Brent (601) and Hertsmere (289).

Collisions on the A4140 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stHarrow1,8212,25927293
2ndBrent601790892
3rdHertsmere289365344
4thBarnet3300

A4140 crashes by town

Collisions on the A4140 were recorded in 3 towns and built-up areas, led by Harrow (1,390) and Brent (482).

Recent crashes on the A4140

These are the 25 most recent collisions on the A4140, from 10 May to 14 December 2025.

Severity