I've ridden in the El Tour de Tucson a few times, but this year I volunteered as a radio operator. Ted AA7HX assigned me to the role of Sector #1 Chief, which turned out to be a very good job for me.
The race has somewhere around 9,000 to 11,000 riders, depending on who you listen to. My Sector covered the first ~30 miles of the 110-mile route. There were 4 aid stations in the Sector, and my job was basically to cruise around helping the radio operators stationed at each aid station. Net Control provided us with directions. We didn't see a lot of action, since the race had just started; later Sectors had more accidents, bike repairs, and food and water problems to deal with.
I started up about 5:30 a.m., and was finished by 11:00. It was especially interesting to work El Tour since I'm currently in the midst of the ARRL Emcomm Level 2 course, which is designed to train operators for proper net control procedures.
The picture shows my truck at aid station #3. The net was on the W7SA 2 meter repeater, and I also ran APRS from the truck along with numerous other hams.