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CrashStats

A4145 accidents: crash map and statistics

Police recorded 701 collisions on the A4145 from 1979 to 2025, with 925 casualties. Of those crashes, 4 were fatal and 143 serious, and 4 people were killed.

In 2025 there were 8 collisions on the A4145, up 33% from 6 in 2024, with 12 casualties.

Collisions since 1979
701
1,506th highest of 4,923 roads
Casualties
925
1.32 per collision
Fatal collisions
4
4 people killed
Serious collisions
143
160 seriously injured
Collisions in 2025
8
Up 33% on 2024
Casualties in 2025
12
Up 100% on 2024

Crash severity on the A4145

On the A4145, 0.6% of collisions were fatal and 20% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal40.6%
  • Serious14320%
  • Slight55479%

Where the A4145 ranks among 4,923 roads

Most collisions
1,506th
Most casualties
1,524th
Most fatal collisions
2,815th
Most serious collisions
1,427th

A4145 accidents by year

Collisions on the A4145 peaked at 30 in 2000 and were down to 8 in 2025.

Collisions and casualties on the A4145, 1979 to 2025

  • Collisions
  • Collisions in 2025: 8
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
2025812
202466
202366
202267
202168
20201113
2019810
201855
201778
201646
2015712
2014912
20131214
20121215
20111321
2010811
200966
20081523
20071518
2006911
20051318
200488
20032434
20022130
20011623
20003044
19992632
19981725
19972838
19962533
19951721
19941923
19931420
19921924
19911417
19901417
19891624
19881719
19872535
19861620
19852031
19842226
19832629
19822431
19811827
19802537
19791415

When crashes happen on the A4145

Friday has the most collisions on the A4145 (128), and 3pm to 6pm is the busiest time of day (174).

Collisions by day of the week

  • Monday98 (14%)
  • Tuesday102 (15%)
  • Wednesday91 (13%)
  • Thursday124 (18%)
  • Friday128 (18%)
  • Saturday89 (13%)
  • Sunday69 (9.8%)

Collisions by time of day

  • Midnight to 3am15 (2.1%)
  • 3am to 6am8 (1.1%)
  • 6am to 9am110 (16%)
  • 9am to noon78 (11%)
  • Noon to 3pm127 (18%)
  • 3pm to 6pm174 (25%)
  • 6pm to 9pm118 (17%)
  • 9pm to midnight71 (10%)

Collisions by month

  • January64 (9.1%)
  • February51 (7.3%)
  • March52 (7.4%)
  • April57 (8.1%)
  • May65 (9.3%)
  • June50 (7.1%)
  • July59 (8.4%)
  • August54 (7.7%)
  • September62 (8.8%)
  • October68 (9.7%)
  • November68 (9.7%)
  • December51 (7.3%)

Light conditions at the time

  • Daylight505 (72%)
  • Dark, street lights lit137 (20%)
  • Dark, no street lighting50 (7.1%)
  • Dark, lighting unknown7 (1%)
  • Dark, street lights unlit2 (0.3%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in A4145 crashes

On the A4145, 72% of collisions happened where the speed limit was 30 mph and 65% on a dry road surface.

Speed limit at the scene

  • 20 mph4 (0.6%)
  • 30 mph505 (72%)
  • 40 mph48 (6.8%)
  • 50 mph4 (0.6%)
  • 60 mph138 (20%)
  • 70 mph2 (0.3%)

Weather at the time

  • Fine, no high winds561 (80%)
  • Raining, no high winds96 (14%)
  • Raining with high winds14 (2%)
  • Snowing, no high winds5 (0.7%)
  • Other19 (2.7%)
  • Not recorded6 (0.9%)

Road surface

  • Dry456 (65%)
  • Wet or damp226 (32%)
  • Frost or ice10 (1.4%)
  • Snow4 (0.6%)
  • Flood over 3cm deep2 (0.3%)
  • Not recorded3 (0.4%)

Type of road

  • Single carriageway640 (91%)
  • Roundabout32 (4.6%)
  • One way street or slip road22 (3.1%)
  • Dual carriageway5 (0.7%)
  • Not recorded2 (0.3%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in A4145 crashes

Car occupants make up 57% of the people killed or injured on the A4145, followed by pedestrians (14%).

Casualties by road user

  • Car occupant523 (57%)
  • Pedestrian133 (14%)
  • Motorcyclist118 (13%)
  • Cyclist84 (9.1%)
  • Van occupant29 (3.1%)
  • Bus or coach occupant17 (1.8%)
  • Other19 (2.1%)
  • Not recorded2 (0.2%)

Vehicles involved

  • Car916 (71%)
  • Motorcycle122 (9.5%)
  • Pedal cycle85 (6.6%)
  • Van or goods vehicle up to 3.5 tonnes81 (6.3%)
  • Goods vehicle over 3.5 tonnes47 (3.6%)
  • Bus or coach12 (0.9%)
  • Other vehicle11 (0.9%)
  • Other16 (1.2%)

Casualties by age

  • 0 to 520 (2.2%)
  • 6 to 1029 (3.1%)
  • 11 to 1551 (5.5%)
  • 16 to 20185 (20%)
  • 21 to 25146 (16%)
  • 26 to 35212 (23%)
  • 36 to 45113 (12%)
  • 46 to 5584 (9.1%)
  • 56 to 6538 (4.1%)
  • 66 to 7530 (3.2%)
  • Over 7513 (1.4%)
  • Not recorded4 (0.4%)

Drivers, passengers and pedestrians

  • Driver or rider607 (66%)
  • Passenger185 (20%)
  • Pedestrian133 (14%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the A4145

Map of the 25 most recent crashes on the A4145

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

  • 25 crashes
  • Serious
  • Slight

A4145 crashes by council area

Collisions on the A4145 were recorded in 2 council areas. Watford has the most, with 486, followed by Three Rivers (211).

Collisions on the A4145 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stWatford486616392
2ndThree Rivers211305150

A4145 crashes by town

Collisions on the A4145 were recorded in 2 towns and built-up areas, led by Watford, Watford (539) and Rickmansworth (30).

Recent crashes on the A4145

These are the 25 most recent collisions on the A4145, from 6 June 2022 to 26 December 2025.

Severity