There are two types of "sections" to drive. Transit sections are your route from one race section to another and then to the final arch at the end of the day. Most turns, signs, markers, and topes are noted in the route book. They are timed in a way - you have an exact amount of time you should take to drive them and you cannot be later than 59 seconds from your calculated arrival time. Also, you cannot be early by any seconds at all. They can be of any distance - we had some 5 kms and some 300+ kms. You have to haul-ass to make it on time. They are not leisurely breaks between race sections - they are basically race sections through towns and with civilian traffic. Wherever possible, the police has intersections blocked off and they waved us past. From time to time, we had police escorts.
Here is a typical transit section in the route book (many pages were nothing but "bumps"):
Velocity sections are the race sections. You get timed, which determines your rank for your class, which determines your starting position for the following day. They are trecherous, fast, but well plotted out in the route book. Every bump, turn, crest, dip, and patch of rough pavement is noted with its distance. Turns are graded from 0-4 - but the grade has to do with difficulty, not radius. A Right 0 might actually have the same radius as a Right 4 - but you have lots of distance to prepare for it, so it's not as difficult. A Right 4 might be a relatively shallow turn, but it comes in quick succession with other turns and therefore is difficult. The route book was written by 2 people, so the grading system was rather subjective. That made things interesting.
Here is a typical velocity section in the route book:
NOT included in the route book are the various obstacles you might come across at 100+ mph in a turn in a velocity section. These obstacles range from the meandering donkey to the fallen tree. Gravel is usually known of ahead of time, so we might get some warning about that. Sometimes you might come upon a disabled race car too - so you had to be very careful.
At the end of one of our race sections on day 1, we were heading towards a left 1 and the checkered flag when we saw a thick plume of black smoke. As we neared the turn, we realized that the smoke was close to the road we were on. Then we saw people waving their arms wildly for us to slow down. As we made the left, we saw that a car was about 50 feet from the road and it was completely engulfed in flames. There are rules about coming across accidents during the race. The rule is to keep going unless the car is on fire and you can see the drivers are still inside. Luckily, the drivers were not inside and medics were already on the scene. It still makes me sick to think about it. The driver and co-driver are ok - a few burns but otherwise ok.
During the week, we saw several cars that had crashed during velocity and transit sections. Every one was a reminder to me that calling out a wrong turn or missing one could have terrible results.