Decode Road Risk quickly

Annualised Comparative Model Output

The primary reporting scale in the app and Results page. It is not an observed annual crash probability.

This is a reporting scale for comparison, not an observed annual crash probability.

Model interpretation

Calibration

Adjusting a model against empirical data. Full collision-history calibration has not yet been completed.

Additional definitions

Centripetal acceleration

The lateral acceleration needed to follow a curve at a given speed.

Additional definitions

Comparative output

A model value used for comparison under defined assumptions; not an official safety rating.

Model interpretation

CSV

A tabular export format for reviewable model values and metadata.

Mapping, context, and export

Curvature

A measure of how strongly a road changes direction over distance.

Additional definitions

Curve/friction speed comparison

A friction-limited curve-speed estimate; not a legal speed limit.

Also: safe speed (legacy wording)

A simplified friction-limited comparison, not a legal speed or driving recommendation.

Additional definitions

Daily interpretive view

A secondary conversion of the annualised model output to make small values easier to read.

Additional definitions

Distribution

The spread of comparative model outputs across sampled roads.

Additional definitions

ECDF / CDF

Cumulative graph views showing the proportion of samples below or above a selected output.

Statistics

Effective friction

The adjusted friction value after surface, weather, or scenario effects are considered.

Additional definitions

Evidence Package

A structured Road Risk export that bundles model output, assumptions, graphs, Maths traces, and context for review.

Additional definitions

Fallback assumption

A visible substitute used when public data is missing or incomplete.

Data quality

GeoJSON

A standard format for exporting geographic geometry and properties.

Additional definitions

Heading change

The change in road direction across the analysed segment.

Additional definitions

Hotspot overlay

A sampled local road-context layer around a chosen place. It is a modelled context view, not an official hotspot declaration.

Additional definitions

Input support

A caution label based on geometry quality, missing tags, fallback assumptions, and completeness.

Also: data confidence (legacy wording)

Describes input completeness and fallback reliance; it is not empirical confidence or safety certainty.

Data quality

Isochrone

A reachability shape showing areas accessible within a time or distance condition.

Additional definitions

Model-to-Observed Comparison

A comparison between modelled samples and nearby historical collision records. It supports review and calibration, not proof of causation.

Additional definitions

Observed Collision Context

A summary of RSA recorded collisions near a selected road or sample geometry under an explicit search radius.

Additional definitions

OpenStreetMap

The open map-data source used for public road geometry and tags.

Additional definitions

OSM tag

A public map-data attribute such as speed, surface, lighting, or road class. Missing tags are unknown context, not proof of real-world absence.

Additional definitions

Overpass API

A public query service used to retrieve OSM road ways, geometry, and tags.

Additional definitions

Percentile

Position inside a sampled comparison set. It is sample-dependent, not a universal ranking.

A high percentile means high within that comparison set, not proven real-world danger.

Statistics

Prospective model

Examines possible comparative signals before collision-history calibration is introduced.

Model interpretation

R.I.S.K.

Roadway Infrastructure Safety Kinematics, the SciFest research project behind Road Risk.

Additional definitions

Radius of curvature

The estimated radius of a bend; smaller radius usually means a tighter curve.

Additional definitions

Relative risk

A comparative indicator under defined assumptions, not an observed crash rate or official road-safety rating.

Additional definitions

Route sample

A modelled section of a generated route used for route comparison under the active assumptions.

Additional definitions

RSA Recorded Collision

A historical recorded collision record from RSA source data. It is observed context, not a model output.

This is historical observed context. It does not prove Road Risk model correctness or official road danger.

Additional definitions

Scenario modifier

A controlled adjustment for rain, fog, fatigue, overspeed, BAC, vehicle type, lighting, surface, or related assumptions.

Additional definitions

Source Manifest

The record metadata that explains export kind, source app, schema/model version, privacy flags, hashes, and loadability.

Additional definitions

Stopping distance

Reaction distance plus braking distance under the active speed, friction, and selected assumptions.

Additional definitions

Traffic proxy

An estimated exposure or context value used when direct traffic counts are unavailable.

Additional definitions

Validation

Testing whether outputs behave correctly and match external evidence. Road Risk currently has internal consistency testing, not operational validation.

Additional definitions