Final answer:
The white sign at a railroad crossing typically advises motorists to look, listen, and prepare to stop if necessary. It aims to enhance safety at crossings by increasing alertness to potential oncoming trains, particularly in densely trafficked areas or near campuses.
Step-by-step explanation:
When you encounter a white sign at a railroad crossing, it typically means that you should look, listen, and prepare to stop if necessary. This indicates that the crossing is not completely controlled by a traffic signal or gate. Therefore, the correct answer would be b) Look, listen, and prepare to stop at the crossing if necessary. While approaching the crossing, you must be alert and ready to yield to any oncoming trains. This is crucial for both the safety of vehicle passengers and pedestrians, especially in areas where traffic is heavy or near schools and campuses where pedestrian traffic is significant.
Installing a traffic signal can address multiple concerns at intersections near railroad crossings. Signals can reduce the speed of approaching vehicles, thus enhancing safety. They also provide clear indications for when it is safe for pedestrians and vehicles to cross, aligning with the model cause-and-effect scenario where traffic signals have been proven to decrease accidents and improve overall pedestrian and driver safety at crossings.