NASCAR Racing: Track position after pits, pace car, pit road

Question
Dear Stooger,   I am a NASCAR freak with Jeff Gordon and Mikey being my favorites.  I have not been able to figure out how where they come back out of the pits affects their track position.  Could you shed some light on that?  Thanks for your help...

Answer
Every car that pits gives up their track position. As they exit pit road they cross a white line at the end of pit road. This line decides where they line up when they pull in behind the pace car. NASCAR keeps a stop action camera directly on that line so there is no question on who crosses it first. Since there is no racing allowed on the track during caution the order is held as they exit pit road.
The most questions I receive occur when there are cars that do not pit and remain on the track. When this happens you often get cars that were a lap down lined up in front of the leader. The reason for this is that as the cars that were on the lead lap go down pit road they give up their track position. The cars that were a lap down that don't pit have in effect gone by the lead lap cars and got their laps back. If they stay on the track the lead lap cars cannot pass them buit must line up behind them. This leaves the cars that stayed out "most of a lap down" but not lapped yet. If they can stay there until the next yellow flag they will get the rest of that lap back when the pace car picks up the leader.
Hope I've answered all your questions. If not, ask again with more specifics and I'll be happy to help.