Runway Visual Range (RVR) is a measurement used in aviation to determine the distance a pilot can see down the runway. It is crucial for assessing visibility conditions during takeoff and landing. RVR is typically reported in meters or feet and helps pilots make informed decisions about whether it is safe to land or take off. RVR is influenced by various factors, including weather conditions like fog, rain, or snow, which can reduce visibility. Airports often use specialized equipment to measure RVR, ensuring that pilots have accurate information to maintain safety during operations.