Proposal to establish a new UN Regulation for vehicles of categories M2 and M3, class B and III designed specifically for carriage of children, to prevent children being left unattended and reduce risk of Pediatric Vehicular Heatstroke. The regulation requires vehicle-based warning systems with Physical Inspection Devices that generate external visual and audible warnings within pre-determined time limits if drivers do not inspect passenger compartments before leaving vehicles. External visual warnings use direction indicator lamps already type-approved; audible warnings use type-approved horns or reverse alarm devices, or must pass specified test procedures. The regulation focuses on physical inspection systems as an intuitive, effective, widely available solution, while remaining technology-neutral to permit future inclusion of other prevention means as they mature.