Mirrors

Vehicles must be equipped with a minimum of 8 square inches of total usable mirror surface area, provided by one or two mirrors.
The mirror(s) must provide the driver with a clear view to the rear on both sides of the vehicle. Visibility will be evaluated by the vehicle inspector and race steward using a method they deem appropriate.
The driver must have a clear and unobstructed view to the front and both sides of the vehicle.
Electronic sensing devices, including video cameras and monitors, may not be used as a substitute for rearview mirrors.

Rulebook