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CrashStats

B4521 accidents: crash map and statistics

Police recorded 235 collisions on the B4521 from 1979 to 2025, with 335 casualties. Of those crashes, 5 were fatal and 74 serious, and 6 people were killed.

In 2025 there were 2 collisions on the B4521, down 50% from 4 in 2024, with 2 casualties.

Collisions since 1979
235
3,033rd highest of 4,923 roads
Casualties
335
1.43 per collision
Fatal collisions
5
6 people killed
Serious collisions
74
90 seriously injured
Collisions in 2025
2
Down 50% on 2024
Casualties in 2025
2
Down 75% on 2024

Crash severity on the B4521

On the B4521, 2.1% of collisions were fatal and 31% serious, against 1.6% and 18% across Great Britain.

Collisions by severity, 1979 to 2025

  • Fatal52.1%
  • Serious7431%
  • Slight15666%

Where the B4521 ranks among 4,923 roads

Most collisions
3,033rd
Most casualties
2,971st
Most fatal collisions
2,545th
Most serious collisions
2,404th

B4521 accidents by year

Collisions on the B4521 peaked at 20 in 1983 and were down to 2 in 2025.

Collisions and casualties on the B4521, 1979 to 2025

  • Collisions
  • Collisions in 2025: 2
  • Casualties

Source: Department for Transport, STATS19 road safety data

View as a table
YearCollisionsCasualties
202522
202448
202322
202211
202145
202000
201922
201822
201736
201622
201511
201455
201322
201222
201136
201024
200958
200823
200756
2006611
200579
200446
2003413
200259
20011012
200056
199956
199867
199756
1996610
1995610
1994715
199358
1992914
199166
1990913
198979
198866
198768
198679
1985513
19841214
19832025
198246
198155
198046
197956

When crashes happen on the B4521

Friday has the most collisions on the B4521 (52), and 6pm to 9pm is the busiest time of day (58).

Collisions by day of the week

  • Monday26 (11%)
  • Tuesday21 (8.9%)
  • Wednesday27 (11%)
  • Thursday29 (12%)
  • Friday52 (22%)
  • Saturday46 (20%)
  • Sunday34 (14%)

Collisions by time of day

  • Midnight to 3am9 (3.8%)
  • 3am to 6am1 (0.4%)
  • 6am to 9am24 (10%)
  • 9am to noon29 (12%)
  • Noon to 3pm45 (19%)
  • 3pm to 6pm46 (20%)
  • 6pm to 9pm58 (25%)
  • 9pm to midnight23 (9.8%)

Collisions by month

  • January17 (7.2%)
  • February12 (5.1%)
  • March13 (5.5%)
  • April15 (6.4%)
  • May26 (11%)
  • June24 (10%)
  • July22 (9.4%)
  • August21 (8.9%)
  • September24 (10%)
  • October17 (7.2%)
  • November21 (8.9%)
  • December23 (9.8%)

Light conditions at the time

  • Daylight167 (71%)
  • Dark, no street lighting40 (17%)
  • Dark, street lights lit27 (11%)
  • Dark, lighting unknown1 (0.4%)

Source: Department for Transport, STATS19 road safety data

Road and weather conditions in B4521 crashes

On the B4521, 65% of collisions happened where the speed limit was 60 mph and 63% on a dry road surface.

Speed limit at the scene

  • 20 mph1 (0.4%)
  • 30 mph76 (32%)
  • 40 mph3 (1.3%)
  • 50 mph1 (0.4%)
  • 60 mph153 (65%)
  • 70 mph1 (0.4%)

Weather at the time

  • Fine, no high winds180 (77%)
  • Raining, no high winds31 (13%)
  • Fine with high winds6 (2.6%)
  • Fog or mist5 (2.1%)
  • Other12 (5.1%)
  • Not recorded1 (0.4%)

Road surface

  • Dry147 (63%)
  • Wet or damp76 (32%)
  • Frost or ice9 (3.8%)
  • Snow2 (0.9%)
  • Flood over 3cm deep1 (0.4%)

Type of road

  • Single carriageway234 (100%)
  • Dual carriageway1 (0.4%)

Source: Department for Transport, STATS19 road safety data

People hurt and vehicles involved in B4521 crashes

Car occupants make up 66% of the people killed or injured on the B4521, followed by motorcyclists (17%).

Casualties by road user

  • Car occupant222 (66%)
  • Motorcyclist57 (17%)
  • Pedestrian30 (9%)
  • Cyclist13 (3.9%)
  • Van occupant8 (2.4%)
  • Goods vehicle occupant (over 3.5 tonnes)2 (0.6%)
  • Agricultural vehicle occupant1 (0.3%)
  • Other2 (0.6%)

Vehicles involved

  • Car287 (73%)
  • Motorcycle55 (14%)
  • Van or goods vehicle up to 3.5 tonnes15 (3.8%)
  • Pedal cycle13 (3.3%)
  • Goods vehicle over 3.5 tonnes10 (2.6%)
  • Agricultural vehicle3 (0.8%)
  • Other vehicle3 (0.8%)
  • Other5 (1.3%)

Casualties by age

  • 0 to 54 (1.2%)
  • 6 to 1010 (3%)
  • 11 to 1512 (3.6%)
  • 16 to 2072 (21%)
  • 21 to 2548 (14%)
  • 26 to 3548 (14%)
  • 36 to 4548 (14%)
  • 46 to 5533 (9.9%)
  • 56 to 6521 (6.3%)
  • 66 to 7518 (5.4%)
  • Over 7520 (6%)
  • Not recorded1 (0.3%)

Drivers, passengers and pedestrians

  • Driver or rider217 (65%)
  • Passenger88 (26%)
  • Pedestrian30 (9%)

Source: Department for Transport, STATS19 road safety data

Map of recent crashes on the B4521

Map of the 25 most recent crashes on the B4521

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

  • 25 crashes
  • Serious
  • Slight

B4521 crashes by council area

Collisions on the B4521 were recorded in 2 council areas. Monmouthshire has the most, with 187, followed by Herefordshire (45).

Collisions on the B4521 in each area, 1979 to 2025
RankAreaCollisionsCasualtiesFatalSerious
1stMonmouthshire187267459
2ndHerefordshire4565115

B4521 crashes by town

Of the 235 collisions on the B4521, 76 were in the built-up area of Abergavenny.

Recent crashes on the B4521

These are the 25 most recent collisions on the B4521, from 20 August 2014 to 6 September 2025.

Severity