The track photographers shoot with DSLRs and high-powered flashes as the cars go by. My hot shoe flash isn't powerful enough to reach out very far so I've had to improvise without it. There is a delicate balance between a shutter speed quick enough to capture the cars in focus and slow enough to let in light, while still keeping ISO noise at bay. At first I was frustrated because I was getting a low percentage of good photos. The solution was a handy feature in my Canon G15: the HQ burst mode. I'd find a single car in the viewfinder and follow it while holding the shutter button down, and get up to 10 shots in the span of about a second. While not every photo turns out, this has improved my success rate enormously.
Since becoming part of the pit personnel I've gained a new appreciation for the sport, but also for the racers and race fans as people, not just a bunch of beer-drinking hillbillies as they are widely painted by more "sophisticated" people. Race fans come to see their driver win, for sure, but they also want to see a fair race and for every driver to get home safely after the dust clears. And that is where my partner and I turn on the lights and get to work.