A friend was driving her pony in the Prelim division, and at one point I had the chance to be a navigator. Schedule problems prevented that from happening, but I was determined to get up and cheer her on for at least one day. I fought through thunderstorms, a missing passport, an insane work schedule, and found an AirBnB room at the last minute to make it happen. I'm so glad I did!
If you don't know, combined driving is like the eventing of the driving world. Day 1 is dressage, patterns in a ring. Day 2 is marathon, with a timed "roads and tracks" section (much like eventing used to be) and then an obsctacle course. Day 3 is cones - driving through cones with tennis balls perched on top, as a timed exercise in precision.
Obstacles are large intricate built environments that drivers have to navigate in a specific way. The pass throughs are lettered: you go through gate A, then B, and so on. You cannot cross a future gate (can't go through C to get to A) but once you pass through, they're dead, and you can reuse them (so you can go through A again to get to C). There is no set path, and part of the course walk is to decide what route you'll take. Drivers make decisions on how their horses move - better to left or right? - the ground they see that day, the way their carriage handles, and where they can shave a corner to get better time versus take a slower route to set them up better for the next turn.
Much like cross-country, marathon day is judged by time and penalty: an overall optimum time for the course, and then penalties within the object. You accrue 1/4 penalty point for each second you spend in the obstacle, and those points are added to your score. So you're incentivized to spend as little time as possible in the obstacle.
I got to see all the obstacles driven but one (which was really far across the lake, no thank you) with singles, pairs, and then four in hand. The four in hands were INSANE. I really think that driving a four in hand through a course like this might be the ultimate expression of horsemanship. There is so much power and precision that you have to balance so exquisitely!
Below, some photos I took during the day.