When someone asks you 'how fast are you riding in/on that vehicle', then your speed at the one hour time trial is a fair answer since speed is usually expressed 'per hour'. It is a distance liked by both experienced and inexperienced riders.

• The start of the one hour time trial is from 10:00 to 11:00. When you collect your transponder, you will hear your exact start time. We try to put the fastest riders last.
• At the start/finish line there will be a large clock that displays the time. When you arrive at the front of the start queue, a race official will confirm your start time. It is very important to remember this time. Write it down. Five seconds before the start time the official will tell you that you are free to depart. Your race starts when your transponder crosses the start/finish line. After one hour has passed, you can quit the race after completing the lap that you are in.
  Bad luck scenario: you started a few seconds late, and thought you finished exactly after 60.00 minutes. Sorry, you did not complete the hour and get a DNF (did not finish). When in doubt, ride an extra lap or extend your last lap by riding a bit slower.
• This is an individual time-trial, and therefore you can't ride closely behind someone else. If you are not overtaking, keep a distance of at least two bike lengths, or you risk a punishment of 30 seconds each time that you are reported by a race official.