What does "RR" indicate in pavement markings near railroad crossings?

Answer: D — no passing zone before the crossing

In this context, "RR" markings on the pavement serve as an important warning for drivers approaching a railroad crossing. The "RR" indicates the presence of a railroad crossing ahead and is a reminder for motorists to exercise caution. Specifically, it denotes a no passing zone, meaning that drivers should not attempt to overtake other vehicles in this area. This is crucial for safety, as passing near a railroad crossing can lead to dangerous situations where a vehicle might not have enough time to stop if a train is approaching. Recognizing the "RR" marking helps maintain safe driving practices and ensures that all road users are alert to the potential hazards posed by trains.