Hello! I am helping organize a collegiate bike race this season. I could use some advice from experienced organizers on a few topics, but the one that I am most unsure about is radio communication between the organizers/marshalls/cops.

Is it standard to rent long-range radios for everyone, or would you suggest using cellphones? Or any other option I haven't thought of? The course is a 9 mile loop, so the farthest that any marshall with be from another marshall is 3 miles, over rolling terrain (no huge hills/mountains, but lots of trees).