What the sporting regulations say:
- Teams may have no more than two cars available for use at any one time.
- Spare cars are not allowed, though teams may bring additional chassis which can be built up in the event of a race chassis being damaged beyond repair.
- Any driver who decides to use another car or whose car has a change of survival cell following the qualifying practice session must start the race from the pit lane.
- No change of car is permitted after the start of the race.