The SCCA rulebook requires a minimum of 5 minutes between runs. This is to allow the car/brakes/tires time to cool. I don't believe there is any safety reason for this, only to prevent an advantage to the driver who has brought his tires and brakes up to temp from having an advantage by immediatly running again. We always permit two driver cars, and each driver can even run two classes. If possible, we try and split their runs between 2 heats, but sometimes both drivers run in the same heat. In that case their runs are seperated by at least 5 minutes. Drivers are not permitted to run two classes in the same heat.
Hope this clears up your question.
SVTGS5
