ISO 26684:2015

Overview

ISO 26684:2015 - Intelligent transport systems (ITS) - Cooperative intersection signal information and violation warning systems (CIWS) - defines the concept of operation, system requirements and test procedures for CIWS at signalized intersections. Published by ISO in 2015, this standard aims to reduce crash risk, injury and property damage by enhancing driver awareness and providing in-vehicle warnings about imminent traffic signal violations. ISO 26684:2015 covers basic functions, functional and performance requirements, information content and test methods for cooperative intersection signal information and violation warning systems.

Key topics and technical requirements

• System scope and classification: CIWS is classified into Class I (information), Class II (warning) and Class III (control/automatic braking - future issues), describing increasing levels of driver support.
• System components: Roles of Roadside Equipment (RSE) and On-Board Equipment (OBE) are defined - RSE supplies signal information; OBE computes need for warnings and presents HMI to drivers.
• Functional requirements: Requirements cover acquisition of vehicle position, travel direction and speed, identification of traffic signal phase and timing, judgement logic for warning activation/deactivation, and human–machine interface (HMI) display contents.
• Performance requirements: Key performance elements include communication range and delay, warning timing and termination, stopping distance and Time To Arrive at Intersection (TTAI) considerations, and definition of warning thresholds to avoid signal violations.
• Test procedures: The standard specifies test vehicle and test site criteria, environmental and geometric test conditions, RSE placement considerations and system-level test methods to validate CIWS performance.

Applications and practical value

• Collision risk reduction: Deploying CIWS improves driver awareness of signal phases and reduces red-light violations at signalized intersections.
• Infrastructure-to-vehicle (I2V) deployments: Municipalities and road authorities can use ISO 26684:2015 to define requirements when equipping intersections with RSEs.
• Vehicle systems and HMI design: Vehicle manufacturers and telematics suppliers use the standard to design OBE logic, warning timing and driver interfaces that meet defined performance criteria.
• Test and validation: Test laboratories and integrators can adopt the standard’s test methods to verify CIWS performance under controlled site and environmental conditions.

Who should use this standard

• ITS planners and traffic authorities
• Vehicle OEMs and telematics suppliers
• Infrastructure vendors and system integrators
• Test houses, safety assessors and regulators

Related standards

ISO 26684:2015 is a system-level ITS standard; it is intended to be used together with communication and traffic-control technical standards (wireless V2I specifications and signal controller standards) when implementing end-to-end CIWS deployments.