they would grade it up before the race. After all the practice was over on Tuesday they graded the track and made it rough again, but now after truck qualifying and other late model races today the track was packed solid again before the truck race. I thought for sure they'd go out there with a grader and loosen the dirt back up.
Once the dirt gets pack solid the rubber coming off the tires stick to it, and the track actually starts turning black. That's the rubber, so once the track is packed solid, and it starts taking on rubber, and has a good rubber build up the cars or trucks are actually racing on top of the rubber, and not dirt. The same thing happens with asphalt. Once the asphalt gets covered with rubber the cars are actually racing on rubber not asphalt. That's why when it rains and washes all the rubber off the track they say the track if fresh and slick again. Remember a few years back at Indianapolis when the cars had to drive slow, and come in every 12 to 15 laps for tires. That was because what ever rubber compound they used to build those tires with they took to INDY wasn't sticking to the track, and the asphalt was just grinding the tires up like a grinding wheel.