Overview
ISO 18868:2013/Amd 1:2020 is an important amendment to the international standard governing commercial road vehicles' coupling equipment used in multiple vehicle combinations. Specifically, this amendment focuses on clarifying the calculation of the V-value when combinations include a centre axle trailer (CAT). Published by the International Organization for Standardization (ISO), this update enhances the strength requirement specifications to ensure reliable and safe coupling between vehicles in complex trailer setups.
This amendment complements the original ISO 18868:2013 standard and provides essential guidance on strength requirements related to the V-value calculation-a critical factor in assessing the mechanical integrity of coupling equipment.
Key Topics
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Commercial Road Vehicle Coupling Equipment
The standard addresses coupling equipment between vehicles in multiple vehicle combinations, ensuring they meet the strength requirements to maintain safety and operational stability.
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Centre Axle Trailer (CAT) Inclusion
This amendment clarifies how to properly calculate the V-value specifically in combinations that feature a centre axle trailer, a configuration with unique load distribution characteristics.
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V-Value Calculation Clarifications
The amendment adds explicit text to sections 5.2.2.2 and 5.2.2.4 of the original standard, stipulating:
- The V-value must be at least 1 if the calculated value is less than 1, ensuring minimum strength criteria are always met.
- Mathematical guidance on how the V-value is derived with certain formulaic elements involving load and length factors.
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Strength Requirement Enforcement
By better defining the V-value calculation, the standard enforces consistent strength assessments, helping manufacturers and regulators ensure coupling devices can withstand operational stresses.
Applications
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Heavy and Light Commercial Vehicle Manufacturing
Manufacturers use this amendment to design and test coupling equipment in compliance with international safety and performance standards for multi-trailer vehicle combinations, including CATs.
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Vehicle Combination Safety Compliance
Regulatory authorities and certification bodies apply ISO 18868:2013/Amd 1:2020 when verifying the safety and strength compliance of commercial truck and trailer couplings.
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Fleet Management and Operations
Fleet operators benefit from adherence to this standard by reducing the risk of coupling failure, leading to safer multi-trailer transport and fewer roadside incidents.
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Engineering and Design of Trailers
Designers integrate these clarified strength requirements early in the vehicle development process to optimize coupling solutions for durability and regulatory adherence.
Related Standards
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ISO 7581:2013 – Covers coupling devices for road vehicles, supporting general test requirements that complement ISO 18868.
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ISO 1726 Series – Governs towing devices for commercial vehicles, providing additional regulatory context for safe trailer coupling systems.
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ECE Regulation 55 – European regulation on mechanical coupling devices, often referenced alongside ISO standards for vehicle safety.
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ISO/TC 22 Road Vehicles Standards – The technical committee responsible for developing ISO 18868 and related documents focusing on road vehicle safety and performance.
Keywords: ISO 18868 amendment, commercial road vehicles coupling, centre axle trailer standard, V-value calculation, vehicle combination strength requirements, coupling equipment safety, multi-vehicle combination standards, ISO commercial vehicle standards, trailer coupling durability
Open preview (PDF)Commercial road vehicles — Coupling equipment between vehicles in multiple vehicle combinations — Strength requirements — Amendment 1: Clarification for calculation for V-value for combinations including a centre axel trailer (CAT)