Overview
ISO 21956:2019 establishes human machine interface (HMI) design specifications for keyless ignition systems that use an electronic key code carrying device. The standard applies to passenger cars (including SUVs and light trucks) and commercial vehicles (heavy trucks and buses), and is independent of propulsion type (ICE, hybrid, electric). It covers normal operation, emergency start/stop, low-battery procedures for the electrical key, prevention of inadvertent actuations, and driver alerts for non-standard situations.
Key topics and requirements
- Definitions and modes: clear terminology for key code, key code carrying device, keyless ignition control, starting system, and ignition modes (start, run, stop, electrical and lower modes such as living/parked/hibernate for commercial vehicles).
- Design guidelines for actuation:
- Prevent accidental starting - require two distinct actions (e.g., brake pedal + keyless control).
- Emergency starting/restarting after unintended stall - provide methods (and at minimum instructions) to restart without key verification.
- Emergency stopping and interruption of starting - allow driver to interrupt start sequence.
- Special provisions for vehicles with power take-offs and automatic start/stop systems.
- Low-battery and failure modes:
- Procedures when the key code carrying device battery runs out, including recommended operation methods (e.g., hold key close to control or use mechanical insertion if supported).
- Mandatory step‑by‑step instructions in owner materials or in-vehicle displays.
- Alerts and driver information:
- Alerts for scenarios such as key left in vehicle, missing key during start, ignition mode active at exit, key leaving vehicle, power shut-off without key, and steering lock status.
- Requirements for auditory/visual alerts and driver communications (owner’s manual, quick start guide, or in-vehicle popups).
- Use cases annex: illustrative keyless ignition use cases to aid implementation.
Practical applications and who uses it
ISO 21956:2019 is intended for:
- Vehicle OEMs and HMI designers specifying push-button and rotary start systems.
- Tier‑1 suppliers of keyless entry/start modules and electronic steering locks.
- UX and ergonomics engineers designing driver alerts and manuals.
- Compliance, safety and validation teams ensuring consistent behavior across models and preventing user-initiated errors.
- Regulators and fleet operators evaluating safety impacts of keyless ignition in commercial vehicle operations.
Practical benefits include improved driver safety, reduced inadvertent vehicle movement, standardized low‑battery solutions, and consistent in-vehicle messaging that reduces user confusion.
Related standards
- SAE J2948 - addresses operation of keyless ignition systems (ISO 21956:2019 complements SAE J2948 with more detailed HMI guidance for emergency, low‑battery and commercial vehicle scenarios).
- Developed by ISO/TC 22 (Road vehicles), Subcommittee SC 39 (Ergonomics).
Keywords: ISO 21956, keyless ignition, HMI, human machine interface, vehicle ergonomics, key code carrying device, start/stop, vehicle safety, alerts.