NASCAR Racing: red flags, red flags, pit road

Question
Do driver's nowmally shut their engines off if there is a red flag and they are stuck out on the track? Specifically during yesterday's race and the red flag at lap 21 do you think that all or most of the drivers shut their engines off during that wait?

Answer
Hi Dan,

If it is a wreck, like lap 21 during the race, then they will stop the cars on the track and they shut the engines off.  After all, if they throw the red flag, that race is going to be stopped for a while.  However, if it is rain, then they pull the cars on pit road, then shut the engines off.  They keep the cars on the track so that the advertisers can't complain that their company was seen during the race.
Hope i helped!
Coy Jordan