ISO 12353-2:2003

Overview

ISO 12353-2:2003 - Road vehicles: Traffic accident analysis - Part 2 provides guidance on selecting and using impact severity measures in road-vehicle crashes. It describes which physical parameters (e.g., closing velocity, change of velocity (Δv), equivalent energy speed (EES), intrusion measures, crash pulse) are suitable to characterise the violence of a first collision (the vehicle impact), summarizes methods to determine those parameters, and explains their relationship to vehicle response and injury outcomes. Annexes include an overview of determination methods (Annex A) and application examples (Annex B).

Key topics and technical requirements

• Definition and scope: Impact severity refers to changes in a vehicle’s physical parameters due to a crash (distinct from injury outcome).
• Severity parameters covered: closing/impact velocity, Δv, EES, damage extent, intrusion extent and intrusion velocity, mean acceleration, crash pulse and derived parameters, contact velocity, biomechanical loads (HIC, VC, TTI) as body-region indicators.
• Suitability guidance: The standard evaluates which measures are appropriate for different impact types (frontal, side, rear, unprotected road-user strikes) and notes limitations (e.g., Δv may be insufficient where compartment intrusion dominates).
• Method selection: Recommends selecting methods that match available input data and desired outputs; combine several relevant measures when possible.
• Uncertainty and confidence: Users must consider measurement uncertainties and confidence levels, especially for parameters estimated rather than directly measured.
• Vehicle response focus: Emphasises use of closing velocity and crash preconditions (mass, angles, contact points) to evaluate crash pulse, deformations and residual damage.

Practical applications

• Accident reconstruction & forensic analysis: Choose and justify impact severity parameters (Δv, EES, intrusion metrics) to reconstruct crash severity and link to occupant outcomes.
• Vehicle design & crashworthiness development: Compare test configurations to real-world impact severities; use measures to evaluate restraint and compartment performance.
• Regulatory & policy evaluation: Assess traffic-calming or infrastructure changes by comparing changes in impact severity on modified roads.
• Safety research & epidemiology: Standardise severity metrics across studies to improve correlation analysis between crash dose and injury response.
• Insurance & litigation: Provide consistent, standard-based measures when quantifying crash violence and potential injury causation.

Users

• Accident reconstructionists, forensic engineers, vehicle manufacturers, regulatory bodies, road safety researchers, insurers and policymakers.

Related standards

• ISO 12353-1:2002 (Vocabulary for traffic accident analysis)
• ISO 6813 (Road vehicles - Collision classification - Terminology)

Keywords: ISO 12353-2:2003, impact severity measures, traffic accident analysis, Δv, EES, crash pulse, intrusion velocity, closing velocity, crashworthiness, accident reconstruction, vehicle response.