ISO 3888-2:2025

Overview

ISO 3888-2:2025 is an international standard published by the International Organization for Standardization (ISO) that defines the test track dimensions and procedures for a severe lane-change manoeuvre specifically focused on obstacle avoidance. It applies to passenger cars and light commercial vehicles up to a gross vehicle mass of 3.5 tonnes, as classified by ISO 3833. This standard provides a closed-loop track design aimed at evaluating a vehicle's ability to perform rapid lane changes and avoid obstacles-which reflects a critical aspect of vehicle dynamics and road-holding performance.

The third edition of ISO 3888-2 revises earlier versions with updated figures, added guidance on environmental condition recording, and enhanced clarity in test methods. The standard fosters repeatable and subjective evaluation of vehicle handling characteristics during dynamic driving scenarios.

Key Topics

• Test Track Design
  The standard specifies a 61-meter closed-loop obstacle avoidance track with five sections. The lane widths dynamically adjust to vehicle width using precise formulas:

  • Section 1 width A = 1.1 × vehicle width + 0.25 m
  • Section 3 width B = vehicle width + 1 m
  • Section 5 width C = max(1.3 × vehicle width + 0.25 m, 3 m)
    Track markings employ cones approximately 500 mm tall to define lane boundaries clearly.

• Obstacle Avoidance Manoeuvre
  The test involves a rapid lane change from the starting lane to a parallel lane and back without displacing cones. The procedure factors in lateral accelerations to assess vehicle lateral dynamics under demanding conditions.

• Test Conditions and Procedure
  Testing must be conducted on smooth, clean, dry asphalt with limited gradients (≤2.5%). Environmental parameters such as wind speed (<5 m/s), ambient temperature, and road surface conditions should be documented for test reliability. The vehicle enters section 1 at minimum 2000 revolutions per minute (r/min) in highest gear, followed by a throttle release 2 m into section 1 to ensure consistent longitudinal velocity measurement.

• Subjective Evaluation Focus
  Due to inherent driver influence and variability in dynamic tests, the standard emphasizes subjective assessment over objective vehicle velocity ranking. It cautions that vehicle speed rankings are not definitive for performance comparison in this test.

• Compliance and Updates
  This edition complements related standards including ISO 3833 (vehicle classification and terminology) and ISO 15037-1 (general vehicle dynamics test conditions). It supersedes ISO 3888-2:2011, incorporating technical and editorial improvements.

Applications

• Vehicle Dynamics Testing
  Automakers and test laboratories use ISO 3888-2:2025 to evaluate and compare vehicle handling during emergency lane-change scenarios. This helps in tuning suspension, steering, and stability control systems to improve safety and driver confidence.

• Obstacle Avoidance Performance Assessment
  The standard aids manufacturers in demonstrating a vehicle's ability to safely execute severe lane changes to avoid road hazards, contributing to advanced driver-assistance system (ADAS) validation.

• Regulatory and Safety Research
  Traffic safety organizations and researchers utilize the test method for developing safer vehicle designs and studying correlations between dynamic behaviour and accident avoidance.

• Quality Control and Vehicle Development
  The repeatable track design enables consistent testing throughout vehicle development cycles, supporting engineering decisions and regulatory compliance.

Related Standards

• ISO 3833:1977 - Road Vehicles - Types - Terms and definitions
  Provides vehicle classification definitions relevant for applying ISO 3888-2 to passenger cars and light commercial vehicles.

• ISO 15037-1:2021 - Road vehicles - Vehicle dynamics test methods - Part 1: General conditions for passenger cars
  Sets general procedures and environmental conditions for dynamic vehicle testing, complementing obstacle avoidance protocols.

• ISO 3888-1 (Part 1) - Severe lane-change manoeuvre -- Part 1: Double lane change
  Covers a related test focusing on lane-change without obstacle avoidance, useful for broader assessment of vehicle dynamics.

Practical Value and Benefits

• Standardized Testing Environment
  Ensures objective comparison of vehicles across manufacturers and models by prescribing exact track dimensions and marking.

• Enhanced Safety Insights
  Provides quantifiable data on a vehicle’s handling limits during critical manoeuvres, supporting the design of safer cars.

• Optimized Vehicle Handling
  Helps engineers develop chassis systems that maintain road-holding and stability under extreme steering inputs.

• Improved Test Repeatability
  Recommendations on environmental condition logging minimize variability, making subjective evaluations more reliable.

• Industry Recognition
  International compliance with ISO 3888-2 strengthens credibility in safety testing and may facilitate regulatory approval where applicable.

ISO 3888-2:2025 is essential for automotive professionals involved in vehicle dynamics testing, safety validation, and chassis development. Adopting this standard supports the delivery of safer passenger cars and light commercial vehicles capable of agile obstacle avoidance during real-world driving conditions.