Which vehicles must stop at all railroad crossings?

The correct answer is that school buses and passenger buses carrying passengers must stop at all railroad crossings. This regulation is in place primarily for safety reasons. School buses transport children who may not be fully aware of their surroundings or the dangers associated with railroad crossings, making it essential for the bus driver to perform a thorough check of the area before proceeding.

Passenger buses also follow the same regulation as they typically carry groups of people, which increases the responsibility of the driver for the safety of all passengers onboard. The requirement to stop allows drivers to ensure that tracks are clear of trains before crossing, significantly reducing the risk of accidents at these potentially dangerous intersections.

In contrast, while trucks carrying hazardous materials are required to stop at many railroad crossings due to the nature of the cargo they carry, they do not stop at every crossing — only at those specifically designated. Not all passenger vehicles are required to stop; it varies based on the vehicle type and situation. Emergency vehicles responding to calls often have exemptions in these circumstances where they can proceed without stopping, as their primary function is to respond rapidly to emergencies.