When no other practicable transportation is available, what is the federal maximum gross weight of any one permitted non-Class 1 hazardous-material class on a passenger-for-hire vehicle?
Correct answer: B – 99 pounds
Federal regulation limits any given non-Class 1 hazardous-material class to 45 kilograms, or 99 pounds, gross weight. The aggregate limit for all such materials is 225 kilograms, or 496 pounds. The South Dakota manual presents these as rounded study figures of 100 pounds per class and 500 pounds total, but the federal regulation supplies the exact limits.
Source: South Dakota Commercial Driver License Manual — § 4.2.2, “Forbidden Hazardous Materials”, 49 CFR § 177.870(e) – Regulations for passenger carrying vehicles

