Overview
ISO 16673:2017 - "Road vehicles - Ergonomic aspects of transport information and control systems - Occlusion method to assess visual demand due to the use of in-vehicle systems" specifies a repeatable procedure to measure visual demand imposed by visual or visual‑manual in-vehicle interfaces while the vehicle is in motion. The standard applies to OEM and after‑market products, permanently installed and portable systems, and accepts any means of visual occlusion (e.g., occlusion goggles, display blanking, mechanical or electronic shutters).
Key topics and technical requirements
- Scope and applicability: Measurement of visual demand for driver‑accessible interfaces when the vehicle is moving; works for prototypes and production systems.
- Measurement procedures: Detailed protocols for set‑up, vision and occlusion intervals, task timing, and criteria for excluding trials.
- Occlusion methods: Intermittent viewing implemented by goggles, variable transmittance lenses, display blanking, or mechanical shutters. Switching/restoration of the display must occur in less than 20 ms.
- Defined metrics:
- TSOT (Total Shutter Open Time) - sum of all vision intervals (time the interface is visible) required to complete a task.
- TTT (Total Task Time Unoccluded / Occluded) - task completion time with and without occlusion procedures.
- Resumability ratio (R) - TSOT divided by TTT_unoccluded (R = TSOT / TTT_Unoccl). R quantifies how easily a task can be resumed after interruption.
- Assessment elements: Selection of representative tasks and goals, participant selection, training, test trials, experimental plan, calculation and interpretation of TSOT and R.
- Supporting guidance: Annex A (system response delay) and Annex B (surrogate driving task) provide further context for experimental design.
Applications and users
ISO 16673:2017 is used to:
- Evaluate and compare driver interfaces (navigation, infotainment, messaging, ADAS HMI) for visual distraction risk.
- Support HMI design decisions to minimize eyes‑off‑road time and improve resumability of tasks.
- Inform safety validation, usability testing, and regulatory or procurement assessments.
Primary users include:
- Automotive OEMs and supplier HMI teams
- Human factors and usability engineers
- Vehicle safety and compliance labs
- After‑market device manufacturers
- Regulators and research organizations studying driver distraction
Related standards
Although ISO 16673 contains no normative references, it cross‑refers to relevant documents for context and definitions, for example:
- ISO 15007‑1 (glance measurement concepts)
- ISO 3958 and SAE J1050 (driver reach/head movement)
Use ISO 16673:2017 alongside eye‑tracking studies for a comprehensive assessment of visual demand and driver distraction.