Final answer:
Passenger vehicles and vehicles carrying explosives or flammable liquids are required to stop at railroad crossings no closer than 15 feet or further than 50 feet.
Step-by-step explanation:
Passenger vehicles and vehicles carrying explosives or flammable liquids are required by law to stop at railroad crossings no closer than 15 feet or further than 50 feet.
These regulations are put in place to ensure the safety of both the vehicles and the train. Stopping at an appropriate distance allows the vehicle to have enough space to clear the tracks and prevents any potential accidents.