Wheel Contact
 

Can we have a non-driven wheel in contact with the floor in this year's project, for the sole purpose of determining actual speed and distance for the robot?

Re: Wheel Contact
 

Yes it can. There have been many references to this exact question both on CD and through the official Q&A. As long as no additional traction is gained, your scenario is perfectly legal.
This message will likely be followed by a litany of "search before you post" posts, as per Internet requirements. Don't be offended; just friendly people trying to help.