Under 49 CFR 383.51(e)'s Table 4, which vehicles are grouped with hazmat carriers and subject to the stricter out-of-service order disqualification penalties?

49 CFR 383.51(e), Table 4 to § 383.51, item (2)

The exact wording of this threshold matters because it's a bright-line seating-capacity rule, not a judgment call about 'how many passengers are on board today.' A driver assigned to a 16-seat (or larger) vehicle is automatically in the stricter penalty bracket for OOS order violations the moment they're behind the wheel, even on a trip with only a few riders.