It depend on weather conditions. Last year, it had snowed a few days before, and melted between that time and the race. The road ended up being pretty soft and made for some sketchy riding. Last year, every time the main field hit the dirt section, the speed would increase by 3-4 mph to try and shake off anyone who wasn't confident with their bike handling skills.
Looking at the forcast, I am extremely glad I'm doing the racetrack race (flying rhino spring training series if you want to google it up.)