Here's the rules for vehicle numbers:

  • Must be numerical (no letters or other special characters)
  • Cannot be zero
  • Cannot be negative
  • No two racers can have the same number, even if they are in different race groups
  • Do not need to be consecutive (you can have number gaps)
  • Cannot have leading zeros (e.g. 007 is treated as 7)
  • Can be very large (there is a maximum number, but it is very large)

Since vehicle numbers do not need to be consecutive, you have the flexibility of letting the racers choose their own vehicle numbers.  Given the chance, though, the kids would love to pick their own vehicle numbers and incorporate it into their design.

If you wish, you can setup each race group with a different series of numbers (e.g. 100 series numbers for one group, 200 series for another, etc.).  That can make it easier to find vehicles during a race.