What constitutes active railroad crossings?

Active railroad crossings are designated by the presence of traffic control devices that actively notify drivers of an approaching train. This includes flashing red lights, bells, and gates that automatically lower when a train is approaching. These features are essential for alerting motorists to the immediate dangers associated with railroads and help to enhance safety by providing a clear signal that a train is on the way.

In contrast, crossings with only warning signs may not provide enough information or urgency for drivers, as they rely on the driver's awareness of train schedules and the need to stop. Crossings that do not have tracks do not pose any danger from trains, and any crossing with a stop sign may not necessarily indicate that a train could be coming through, as those signs might serve different traffic regulations. Therefore, the defining characteristic of an active railroad crossing is the incorporation of these traffic control devices, making option B the correct choice.