What types of vehicles must stop at all railroad crossings?

School buses and hazardous materials vehicles must stop at all railroad crossings due to the potential risk involved with crossing train tracks. This requirement is in place to ensure the safety of passengers, particularly children, and to prevent catastrophic accidents involving hazardous substances. These vehicles typically carry vulnerable passengers or hazardous materials that could pose serious dangers in the event of a collision with a train.

Emergency response vehicles, private cars, and motorcycles, while still needing to approach railroad crossings with caution, do not have the same mandatory stopping requirement. Emergency vehicles may proceed if they are responding to an emergency and can do so safely, while private cars and motorcycles are expected to stop if there are signals indicating a train is present or if the crossing is deemed unsafe. However, they do not have the same rules as school buses and vehicles transporting hazardous materials, which prioritize additional safety measures due to their contexts.