Under Caution Meaning in NASCAR

Under caution describes a period when racing stops for a track hazard. Officials wave a yellow flag to slow down the entire field. Cars must line up behind a lead vehicle at a slow. This time allows workers to clean debris or move crashed cars. One race might go under caution because of a sudden rain shower. Drivers cannot pass each other until the green flag waves again. Teams often use this time to enter the pits for service. This period saves fuel and reduces the wear on the racing engines. Resuming the race after a caution leads to very exciting restarts.