Final answer:
In a large commercial vehicle, stopping at least 5 meters before railroad tracks is the correct safety procedure, regardless of whether a train is in sight, due to increased stopping distances for heavy vehicles and pedestrian safety concerns.
Step-by-step explanation:
When approaching a crossing in a large commercial vehicle and noticing a STOP sign on the opposite side of the tracks, the appropriate action is to stop at least 5 meters before the tracks. It is crucial to adhere to this rule even if a train is not in sight as commercial vehicles require a greater stopping distance, and there may be other factors such as crossing gate malfunctions or obstructed views that can increase risks. It's important for the safety of the driver and others.
The reason why this action is important is closely tied to traffic and pedestrian safety. In areas near crossings, vehicles must adhere to stop signs and signals to prevent accidents and ensure that pedestrians can cross safely. Additionally, the physics of a large vehicle's braking distance should be considered, as it takes longer for a heavy vehicle to come to a complete stop even under emergency braking conditions.
In the context of a vehicle approaching and it's only 28 meters away, it's best to err on the side of caution and not cross the road, as cars can cover that distance rapidly, depending on their speed. Pedestrian safety is paramount, and one must always ensure sufficient distance and time for the vehicle to pass before attempting to cross the street.