Common Accident Data Set (CADaS) Reference Guide

common_accident_data_set_cadas.pdf

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The attached document, "common_accident_data_set_cadas.pdf," is the official Reference Guide for the Common Accident Data Set (CADaS), Version 3.7, dated November 2018. CADaS is a standardized framework developed to harmonize road accident data collection across European Union (EU) countries, supporting the European Commission’s CARE database on road accidents.

Background and Purpose

• Road accident data in the EU has historically been collected using diverse national systems, leading to incompatibilities and difficulties in cross-country comparisons.

• The CARE database, established in 1991, ag

  gregates disaggregated national accident data, but differences in definitions, structures, and formats have limited its analytical potential.

• CADaS was created to address these issues by defining a minimum set of standardized variables and values for road accident data, enabling more reliable and comparable analysis at the European level.

Scope and Implementation

• CADaS is a voluntary standard: EU countries are encouraged, but not required, to adopt it in their national systems.

• The framework allows for the gradual integration of more harmonized data into CARE, improving data quality and comparability over time.

• Countries can continue using their national systems and submit data in their own formats, but are encouraged to map and transform their data to the CADaS structure when transmitting to the EC.

Structure of CADaS

CADaS organizes accident data into four main categories, each with a unique code:

• A: Accident-related variables

• R: Road-related variables

• U: Traffic unit (vehicle and pedestrian)-related variables

• P: Person-related variables

Each variable is assigned an importance level:

• (H): High importance for road safety analysis

• (L): Lower importance

The structure is designed for flexibility, allowing countries to provide data at varying levels of detail using "detailed" or "alternative" (aggregated) values.

Key Components and Variables

The guide details 77 variables and over 500 attribute values, including:

• Accident Information: ID, date, time, location (NUTS/LAU codes), weather, light conditions, accident type (pedestrian, parked vehicle, single/multiple vehicles, hit & run), etc.

• Road Information: Location (latitude/longitude), road class, speed limits, motorway/urban area status, junction details, surface conditions, number of lanes, presence of tunnels/bridges, work zones, curves, and gradients.

• Traffic Unit Information: Vehicle type, special function (e.g., taxi, bus, emergency), trailer, engine power, safety equipment, make/model, registration year, maneuver prior to accident, insurance, hit & run status, registration country.

• Person Information: Person ID, date of birth, gender, nationality, injury severity, road user type, alcohol/drug test results, license details, safety equipment use, seating position, distraction, impairment, journey purpose, MAIS injury scale.

Data Processing and Submission

• The guide provides a step-by-step process for transforming national data into the CADaS structure and submitting it to the European Commission via specified templates (Excel/CSV) and the eDAMIS web portal.

• Quality checks are performed by the EC before data is loaded into the CADaS database.

• Correction factors for fatal and serious injuries are detailed for certain countries to standardize reporting (e.g., adjusting for deaths within 30 days).

Annexes and Reference Materials

The document includes several annexes:

• Diagrams of junctions and interchanges

• Accident type sketches

• E-road reference lists

• Active safety equipment systems

• Guidance on reconciling national definitions with CADaS definitions

Development and Acknowledgements

CADaS was developed by a consortium of European road safety experts and institutions under the EC co-funded SafetyNet project, with ongoing support from the EC Road Safety Unit and CARE team.

Summary Table: CADaS Variable Categories

Category	Code	Examples of Variables
Accident	A	Date, time, location, weather, light, accident type
Road	R	Road class, speed limit, junction, surface, lanes
Traffic Unit	U	Vehicle type, function, safety equipment, manoeuvre
Person	P	Age, gender, injury severity, alcohol/drugs, license

Key Takeaways

• CADaS is the EU’s recommended standard for road accident data, aiming to improve the comparability and analytical value of accident statistics across Europe.

• It covers all critical aspects of accident events, the road environment, involved vehicles, and persons.

• Adoption is voluntary but strongly encouraged, with flexible mechanisms for integrating national data at different levels of detail.

• The guide is a comprehensive technical reference for road safety experts, statisticians, and policymakers involved in accident data collection, reporting, and analysis.