RAS0403: collisions and casualties by local authority
Department for Transport: RAS0403: collisions and casualties by local authority ↗THE ACTUARY LENS · GEOGRAPHIC RISK
Beyond Postcodes
Location is a container of different risk mechanisms—not an explanation by itself. The public road evidence can test geographic differences and persistence; it cannot establish an insurer pricing lift.
Read the explanation, evidence and limitations
A postcode contains several different risks
Location can conceal road use, environment and other hazards. Separating those mechanisms makes geographic differences easier to understand and test.
What changed in the evidence?
Local authority motor vehicle mileage
Department for Transport: Local authority motor vehicle mileage ↗RAS0302: road-type collision and casualty rates
Department for Transport: RAS0302: road-type collision and casualty rates ↗Insurance implication
Geographic differences may capture several distinct risk mechanisms.
Current response: Test
Watch next: Reassess after decomposed geographic features improve later, held-out claims.
Collision location is not the policyholder’s home exposure or an insurer price factor.
Infographic updated: Not separately recorded for this release. Data periods: 2016–2025. Source checks and unrelated publications do not reset the infographic date.
Released sources
Department for Transport: RAS0403: collisions and casualties by local authority ↗Department for Transport: Local authority motor vehicle mileage ↗Department for Transport: RAS0302: road-type collision and casualty rates ↗Office for National Statistics: Counties and Unitary Authorities December 2025 boundaries ↗Met Office: Rainfall — England ↗Met Office: Rainfall — Wales ↗Met Office: Rainfall — Scotland ↗Met Office: Air frost — England ↗Met Office: Air frost — Wales ↗Met Office: Air frost — Scotland ↗Met Office: Wet days ≥1 mm — England ↗Met Office: Wet days ≥1 mm — Wales ↗Met Office: Wet days ≥1 mm — Scotland ↗Home Office: Recorded vehicle offences by police force ↗Office for National Statistics: Police Force Areas December 2023 boundaries ↗Environment Agency: Properties in river and sea flood hazard ↗Environment Agency: Properties in surface-water flood hazard ↗Department for Transport: STATS19 annual releases ↗Department for Transport: Road safety table index ↗Police.uk: Police street-level crime ↗Environment Agency: River and sea flood hazard ↗Environment Agency: Surface-water flood hazard ↗Department for Transport: Resident travel and rural/urban classification ↗DVSA: Anonymised MOT data ↗Download the underlying released evidenceINSURANCE IMPLICATIONS
The actuarial conclusion
- Direction
- Geographic differences may capture several distinct risk mechanisms.
- Magnitude
- Public road-outcome differences are not insurer pricing relativities.
- Timing
- Annual evidence supports a held-out geographic study.
- Evidence
- Authority-level collisions and traffic; not residential policy exposure.
- Response
- Test before changing portfolio assumptions.
What would change this view? Reassess after decomposed geographic features improve later, held-out claims.
Data period2016–2025Latest source check2026-09-23Assessment last changedNo separate change date recorded
Different road outcomes
The approved 2016–2025 authority-level evidence aligns police-reported injury collisions with motor vehicle miles. Compare frequency, serious injury and traffic separately in the Lab.
What drives the difference?
A location factor can mix exposure, road environment, behaviour, severity and correlated hazards. A more useful pricing question tests those components individually and asks whether differences persist in later years.
No claims lift claimed
These public measures are not postcode-level insurer claims or resident mileage. A pricing benefit would need held-out claims, credible exposure and governance on an insurer’s own portfolio.
Inspect the evidence
Use the Lab for the interactive maps, annual series, source records and study protocol. Filters from an older map link are carried into the Lab.
Open Postcode Risk Lab →To explore how road outcomes change over time, continue to Road Risk →
UPDATES
Evidence and assessment changes
Evidence record
Dates and periods are recorded with the individual sources. New evidence can update observations without changing the insurance conclusion.
Assessment change
This release does not record a separate dated change to the insurance conclusion. The revision trigger above describes what would justify reassessment.