This paper contains Part 2 of a two-part paper series proposing potential
regulatory approaches for occupant safety in Automated / Autonomous Vehicles
(AVs) with unique seating configurations (stagecoach and campfire seating). Part
2 focuses on interior safety sensing, associated messaging, and ride control
approaches both prior to and during a ride. Assessments are also proposed after
significant vehicle braking and crash events.
The proposed conditions are to be assessed in a static vehicle environment with
humans segmented by occupant size and an infant dummy. On the vehicle seat and
on the vehicle floor occupant detection conditions are proposed along with
restraint usage detection conditions for vehicle seat belt usage, Child
Restraint Seat (CRS) usage, CRS seat belt usage, and Lower Anchors and Tethers
for Children (LATCH) system usage. These conditions may be detected by sensors /
computer algorithms and human monitoring and thus are technology agnostic. The
topics of animal detection and cargo detection are also discussed.
Part 1 of this paper series (SAE paper 2026-01-0578) proposed using interior
safety sensing as an alternative / a replacement for the National Highway
Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standard 208
(FMVSS-208) Occupant Crash Protection unbelted in-position occupant compliance
conditions. This paper proposes conditions involving occupant and seat belt
restraint usage detection. This evaluation approach strives to prevent unbelted
occupants and is an improvement over restraint countermeasures for unbelted
occupants.
This paper also discusses and proposes visual and audible safety messaging for
prior to the ride occupant education and for occupant and restraint usage
detection outcomes. Vehicle level ride control actions are suggested such as
preventing a ride when improperly restrained occupants are detected.
These approaches can be used in industry-wide regulatory next step contemplation
for unique interior seating arrangement AVs. When adopted, these approaches
would likely reside in an expanded version of FMVSS-208.