Idaho Code § 49-427: Registration card to be carried.

The registration card issued for a vehicle required to be registered by the provisions of this chapter shall, while the vehicle is being operated upon a highway, be in the possession of the driver or carried in the vehicle and be subject to inspection by any peace officer. A person who is issued a registration card electronically shall print the registration card, and such printed copy may be used to satisfy the provisions of this section. For drivers of commercial vehicles registered pursuant to section 49-434 or 49-435, Idaho Code, an electronic format of the registration card is permitted.