I've been in some incredibly fast, sweeping SCCA autocrosses, but it depends more on the available lot than anything else. A postage-stamp site like what's available in Phoenix makes for very tight courses with practically nothing in the way of straights. Stadium lots like we had available for a time in Kansas City allowed for much more open, flowing courses and even some straigtaways, and "freeway speeds" at SCCA events was understood to be a strong suggestion, not a hard speed limit. I saw 70 mph fairly regularly in a street car. Very narrow sites or airport runways like the site in the video allow for little other than slalom, slalom, slalom, turn around, slalom, slalom, slalom, turn right, slalom, slalom, etc. Again, more dependent on the site than the club.