What is the meaning of "throw a caution flag" in
this:
"He was leading with seven laps remaining when NASCAR
threw a caution flag for a crash between Jeff Gordon and Clint Bowyer, setting up a green-white-checkered restart. "
I understand that for sports car racing, if there is some problems on the race track, someone would go out and show/fly/wave a yellow color flag (caution flag). But does '
throw a caution flag' also mean 'show/fly/wave a caution flag', or does it mean something else?