The 107th running of the Indianapolis 500 was red-flagged after a massive crash involving Felix Rosenqvist and Kyle Kirkwood that sent a tire flying over the Turn 2 fence. Kirkwood's car was turned upside down.

So what does it mean when a red flag comes out at the Indianapolis Motor Speedway? Like for anyone driving, red means you must stop. The red flag will often come out due to an on-track incident or weather.

What about the other flags?

Green: Go! Let the race begin.

Yellow: Caution, signaling hazardous conditions. Cars must slow immediately and yield to safety vehicles until the green flag is displayed.

Indy 500: Loose tire flies over fencing, fans after late race crash

Blue: The “passing” flag, signaling a slow driver to make room for a faster car to pass.

Black: Directs a driver to head to the pits and consult with race officials.

Black flag with white X: A driver has been disqualified; officialshave stopped scoring the car until further notice.

Red and yellow striped flag: A substance such as oil or water has made the track slippery.

White: There is one lap left in the race.

Checkered: The race is over.

This article originally appeared on Indianapolis Star: Indy 500 2023: What does a red flag mean at IMS?