Our (student) coach has several roles during the match:
1. Communicate with the other coaches as to scoring/defense opportunities and strategy changes.
2. To communicate any of those opportunities/changes to the drivers
3. To watch all of the other robots on the field to avoid hazards/traffic jams
4. To watch the score to make any necessary strategy changes (this year he played a big role in telling us whether we should place or hurdle again once the match started getting down there)
5. To encourage/constructively criticize the drivers to further enhance their performance, and to keep a positive mindset whenever possible.
Oh, and 6. To be AWESOME!
I can definitely say (as a driver this year) that the actions/words of my coach helped us win matches and have a fun time down on the field! (we might happen to have a cheer just for him......

)
J-O-S-H G-O-O-D-M-A-N, JOSH GOODMAN, HEY HEY JOSH GOODMAN, WOOO!

-Theo
Edit: I guess my list is more of just what he does during the match, obviously his role is very evident before the match as well.