S4.Definitions.Occupant compartment means a space within the vehicle interior intended for driver and passenger use, excluding any space occupied by fixed appliances such as bars, kitchenettes, or toilets.
Over-the-road bus means a bus characterized by an elevated passenger deck located over a baggage compartment.
Prison bus means a bus manufactured for the purpose of transporting persons subject to involuntary restraint or confinement and has design features consistent with that purpose.
School bus is defined in § 571.3 .
School bus derivative bus means a bus that meets Federal motor vehicle safety standards for school buses regarding emergency exits (§ 571.217 ), rollover protection (§ 571.220 ), bus body joint strength (§ 571.221 ), and fuel system integrity (§ 571.301 ).
Stop-request system means a vehicle-integrated system for passenger to use to signal to a vehicle operator that they are requesting a stop.
Survival space means all points within a three-dimensional space in the occupant compartment as defined within the following volume:
(1) The front boundary of the survival space is a transverse vertical plane forward of the most forward seat (whether passenger, or driver seat) when the seat back is in the manufacturer's nominal design riding position. This transverse vertical plane is:(i) For a forward-facing seat, 600 millimeters (mm) in front of the forward most point on the longitudinal centerline of the front surface of the seat back when the seat is in its forward most position;(ii) For a rearward-facing seat, through the most forward point (relative to the vehicle) on the longitudinal centerline of the seat back when the seat is in its forward most position with respect to the vehicle;(iii) For a side-facing seat, through the most forward point (relative to the vehicle) on the seat, including the seat back, seat arm rest, and seat cushion.(2) The rear boundary of the survival space is the inside surface of the rear wall of the occupant compartment of the vehicle.(3) The outer boundary of the survival space at any transverse cross section between, or at the front and rear boundaries, is defined on each side of the vehicle by the occupant compartment floor and the following three line segments (see Figure 1 of this section, provided for illustration purposes only): (i) Segment 1 extends vertically from the floor to an end point that is 500 mm above the floor and 150 mm inboard of the side wall.(ii) Segment 2 starts at the end point of Segment 1. The end point of Segment 2 is 750 mm vertically above and 250 mm horizontally inboard of the end point of Segment 1.(iii) Segment 3 is a horizontal line that starts at the end point of Segment 2 and ends at the vertical longitudinal center plane of the vehicle.Transit bus means a bus that is equipped with a stop-request system sold for public transportation provided by, or on behalf of, a Federal, State, or local government and that is not an over-the-road bus.