Analysis examined 14 cases in Japan where child fatalities occurred after children were left unattended in passenger vehicles of category M₁ and N₁ between January 1984 and April 2025. Indirect sensing could potentially have generated an alert in 13 cases, while direct sensing could potentially have generated an alert in 5 cases. Based on these findings, retaining indirect sensing as an option for UNR is proposed.

Proposal to establish requirements for in-direct plus or direct sensing systems to detect children left unattended in M1 and N1 vehicles under 3,500 kg. Systems shall detect Child Occupants Left Inside (CLIV) events for rear seating positions accommodating child restraint systems and issue audible or audible and visual warnings at least 60 dB(A) within 15–30 seconds of locking all doors, lasting at least 10 seconds and repeating every 90 seconds for at least 20 minutes unless cancelled. The default system setting shall be ON, with deactivation available temporarily for single journeys or long-term for maximum 30 days. Testing shall use CLIV surrogates aged 0, 3, and 6 years per ISO 26315, covering multiple test scenarios including warning delay, cancellation, and temporary deactivation.