Friday night, my daughter and I left the males in our family at home to fend for themselves and took ourselves to the local stock car races for our annual girls' night out. I didn't grow up with car racing and I know almost no one who is familiar with them, so each annual visit is a learning experience as I try to sort it all out. Last year, I came home and promptly looked up the flag codes on Wikipedia - but this year, I realized that the race starter wasn't using the same ones Wikipedia does, so we had to figure them out ourselves.
When the cars first come out on the course before a race, they parade around for several laps to give the audience a chance to pick favorites to cheer for (or maybe to make sure the cars are running well). When the starter is ready for them to line up in pairs, he holds a furled green flag in one hand and a furled yellow flag in the other, then flips them back and forth - his body language makes the goal obvious, even if you don't know the flag code. Once the pairs are all in order, he holds the furled green flag over the course to indicate that the next lap is the start. On the next lap, the unfurled green flag is waved madly just as the front cars reach the starting point (an orange cone on the edge of the track, which an official then tows out of the way with a string) and the cars accelerate hard.
If there is a mis-start - a car starts accelerating too soon, or there is an accident within the first lap - then all the cars line up in pairs again, just like the first time, except that the car that caused the problem goes to the back of the line. This can be a huge penalty: one car that started in front and was leading nicely was then sent to the back of the line and ended the race way back.
Any time there is an accident, the yellow flag comes out and all the cars slow down while the drivers figure out what is going on; this can last for 8-10 laps if untangling an accident is complicated. Except sometimes, a driver doesn't see the flag and goes racing around other cars until the odd behavior of the other drivers sinks in and he (almost always he, but not quite) slows down too. When the yellow flag is out, the cars have to maintain the order they were in when it first came out, including letting cars "cut in" if they got out of order. We never saw the red flag that would stop all the cars. Once the cars are back on the track, or towed to the center, or the debris is off the track, the starter uses the furled and then unfurled green flags to get things started again. The amazing thing is how few serious accidents there were, and how often the cars came right back out on the track to finish the race; sometimes the body work was flapping wildly, but only once did that make a car leave the race, when a crunched, non-aerodynamic front left fender caused the wheel to leave the ground with disconcerting regularity.
When the front car catches up with the slowest car, lapping it, the starter holds out a blue flag with a large yellow-orange spot in the middle; the slower driver is apparently supposed to yield to the faster one, and the starter is always emphatic about which car he means the flag for. When the laps are half run, the starter holds up furled green and white flags and crosses them to indicate the half-way point. The unfurled white flag means "last lap", and of course the checkered flag means "finish".
Once we figured out what the flags meant, the races were a lot more fun to watch, since we had some idea of what was going on. Now if I could just find out what furled black (or blue) and yellow flags, crossed, means.