Final answer:
You must stop at railroad crossings marked with a stop sign and proceed only once you've confirmed no train is approaching, no pedestrians are in the vicinity, and there's enough space across the tracks.
Step-by-step explanation:
At railroad crossings that are only marked with a stop sign, you should stop and then proceed only when you determine that no train is approaching, no pedestrians are approaching, and there is enough room for your vehicle on the opposite side. Ensuring that no train is coming is crucial for safety, as trains often travel at high speeds, and their approach may not be immediately apparent. Pedestrian safety is also paramount, and traffic regulations require that you ensure that no pedestrians are attempting to cross before you move through the crossing. Finally, confirming that there is adequate room on the other side of the tracks ensures that you do not get trapped on the tracks if traffic ahead comes to a stop.