ISO 23456-1:2021

Overview

ISO 23456-1:2021 - "Dynamic signs in physical environments - Part 1: General requirements" defines ergonomic principles for dynamic signs and dynamic signage used in physical spaces. The standard addresses how responsive, changing displays (flashing, motion, scrolling, colour/brightness or content changes) should be designed so information remains visible, safe and accessible as environmental conditions vary (e.g., illumination, crowd density). It explicitly excludes static signs and safety signs for marking escape routes, and does not apply to head‑mount, glasses or hand‑held displays.

Key topics and technical requirements

• Visibility - core requirements are split into four sub‑factors:
  • Conspicuity: attract attention (flashing, motion, zoom, placement)
  • Distinctiveness: avoid confusion between signs (colour, size, repetition, motion speed)
  • Legibility: readable characters and symbols (font style, size, number of characters)
  • Comprehensibility: understandable messages (clear wording, pictograms, multilingual support)
• Visual image safety - protect vulnerable viewers from adverse effects, including considerations to avoid:
  • photosensitive seizures
  • visually induced motion sickness and balance disorders
  • misuse or misleading presentations
• Accessibility - ensure dynamic presentations work for diverse users and contexts (age, culture, disability); recommendations include multiple languages, culturally appropriate pictograms and assistive presentation modes
• Dynamic presentation types and constraints - operational guidance for movement, temporal variation (brightness/chromaticity), lead/presentation time, display location, contrast/luminance and avoidance of discomfort or annoyance
• Design elements - recommendations for graphical symbols, fonts, display methods and how to adapt content to environmental conditions

Applications

ISO 23456-1 is directly applicable to the design and deployment of dynamic signage used to provide caution, guidance and information in:

• Road traffic systems and variable message signs
• Public buildings (stations, airports, malls)
• Outdoor public spaces and pedestrian guidance
• Industrial facilities and factories (safety advisories, operational alerts) Dynamic signs are intended for advance indication (not as the sole means for critical warnings) and for improving safety and user convenience through adaptive displays.

Who should use this standard

• Signage and digital display manufacturers
• Content creators and UX designers for physical displays
• Safety and facility managers, transport authorities, urban planners
• Human factors / ergonomics and accessibility specialists
• Regulators and standards bodies developing site‑specific numeric criteria

Related standards

• ISO 3864‑1 (safety sign design principles)
• ISO 3864‑4 (colorimetric and photometric properties)
• ISO 30061 (related recommendations)
• ISO 7010 (static safety sign sizing referenced in the introduction)

Keywords: ISO 23456-1, dynamic signs, dynamic signage, ergonomics, visibility, accessibility, visual image safety, adaptive displays, signage standards.