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CrashStats

B4251 accidents: crash map and statistics

Police recorded 413 collisions on the B4251 from 1979 to 2025, with 566 casualties. Of those crashes, 11 were fatal and 100 serious, and 14 people were killed.

In 2025 there were 8 collisions on the B4251, up 14% from 7 in 2024, with 10 casualties.

Collisions since 1979
413
2,254th highest of 4,923 roads
Casualties
566
1.37 per collision
Fatal collisions
11
14 people killed
Serious collisions
100
119 seriously injured
Collisions in 2025
8
Up 14% on 2024
Casualties in 2025
10
Down 17% on 2024

Crash severity on the B4251

On the B4251, 2.7% of collisions were fatal and 24% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal112.7%
  • Serious10024%
  • Slight30273%

Where the B4251 ranks among 4,923 roads

Most collisions
2,254th
Most casualties
2,229th
Most fatal collisions
1,595th
Most serious collisions
1,914th

B4251 accidents by year

Collisions on the B4251 peaked at 17 in 2006 and were down to 8 in 2025.

Collisions and casualties on the B4251, 1979 to 2025

  • Collisions
  • Collisions in 2025: 8
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
2025810
2024712
202378
20221316
2021910
202089
20191218
20181212
201748
201668
2015711
2014912
201368
20121015
201189
2010810
200922
20081626
20071016
20061725
2005411
20041016
200367
2002810
2001912
200078
19991325
19981121
19971116
19961012
19951018
19941415
1993911
1992911
1991810
1990813
1989711
198888
198766
198689
198588
19841113
198344
198256
198145
19801316
19791319

When crashes happen on the B4251

Monday has the most collisions on the B4251 (73), and 3pm to 6pm is the busiest time of day (99).

Collisions by day of the week

  • Monday73 (18%)
  • Tuesday59 (14%)
  • Wednesday61 (15%)
  • Thursday62 (15%)
  • Friday73 (18%)
  • Saturday50 (12%)
  • Sunday35 (8.5%)

Collisions by time of day

  • Midnight to 3am13 (3.1%)
  • 3am to 6am5 (1.2%)
  • 6am to 9am47 (11%)
  • 9am to noon56 (14%)
  • Noon to 3pm91 (22%)
  • 3pm to 6pm99 (24%)
  • 6pm to 9pm50 (12%)
  • 9pm to midnight52 (13%)

Collisions by month

  • January34 (8.2%)
  • February48 (12%)
  • March32 (7.7%)
  • April36 (8.7%)
  • May39 (9.4%)
  • June27 (6.5%)
  • July34 (8.2%)
  • August34 (8.2%)
  • September34 (8.2%)
  • October25 (6.1%)
  • November39 (9.4%)
  • December31 (7.5%)

Light conditions at the time

  • Daylight290 (70%)
  • Dark, street lights lit103 (25%)
  • Dark, lighting unknown7 (1.7%)
  • Dark, street lights unlit7 (1.7%)
  • Dark, no street lighting6 (1.5%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in B4251 crashes

On the B4251, 81% of collisions happened where the speed limit was 30 mph and 58% on a dry road surface.

Speed limit at the scene

  • 20 mph11 (2.7%)
  • 30 mph335 (81%)
  • 40 mph25 (6.1%)
  • 50 mph2 (0.5%)
  • 60 mph39 (9.4%)
  • 70 mph1 (0.2%)

Weather at the time

  • Fine, no high winds298 (72%)
  • Raining, no high winds69 (17%)
  • Raining with high winds12 (2.9%)
  • Snowing, no high winds5 (1.2%)
  • Other23 (5.6%)
  • Not recorded6 (1.5%)

Road surface

  • Dry239 (58%)
  • Wet or damp154 (37%)
  • Frost or ice12 (2.9%)
  • Snow7 (1.7%)
  • Flood over 3cm deep1 (0.2%)

Type of road

  • Single carriageway392 (95%)
  • Roundabout15 (3.6%)
  • Dual carriageway5 (1.2%)
  • One way street or slip road1 (0.2%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in B4251 crashes

Car occupants make up 65% of the people killed or injured on the B4251, followed by pedestrians (15%).

Casualties by road user

  • Car occupant366 (65%)
  • Pedestrian85 (15%)
  • Motorcyclist60 (11%)
  • Bus or coach occupant22 (3.9%)
  • Cyclist16 (2.8%)
  • Van occupant8 (1.4%)
  • Goods vehicle occupant (over 3.5 tonnes)3 (0.5%)
  • Other6 (1.1%)

Vehicles involved

  • Car555 (80%)
  • Motorcycle57 (8.2%)
  • Van or goods vehicle up to 3.5 tonnes25 (3.6%)
  • Bus or coach19 (2.7%)
  • Pedal cycle17 (2.4%)
  • Goods vehicle over 3.5 tonnes9 (1.3%)
  • Other vehicle6 (0.9%)
  • Other10 (1.4%)

Casualties by age

  • 0 to 59 (1.6%)
  • 6 to 1016 (2.8%)
  • 11 to 1539 (6.9%)
  • 16 to 20128 (23%)
  • 21 to 2569 (12%)
  • 26 to 3585 (15%)
  • 36 to 4572 (13%)
  • 46 to 5556 (9.9%)
  • 56 to 6535 (6.2%)
  • 66 to 7532 (5.7%)
  • Over 7521 (3.7%)
  • Not recorded4 (0.7%)

Drivers, passengers and pedestrians

  • Driver or rider319 (56%)
  • Passenger162 (29%)
  • Pedestrian85 (15%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the B4251

Map of the 25 most recent crashes on the B4251

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

  • 25 crashes
  • Serious
  • Slight

B4251 crashes by council area

Of the 413 collisions on the B4251, 411 were in Caerphilly.

Collisions on the B4251 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stCaerphilly41156411100

B4251 crashes by town

Collisions on the B4251 were recorded in 5 towns and built-up areas, led by Oakdale (93) and Blackwood (81).

Recent crashes on the B4251

These are the 25 most recent collisions on the B4251, from 30 November 2022 to 14 November 2025.

Severity