Section R. 408.12134 - Parking brakes; tiresRule 2134.
(1) The parking brake on a sit-down rider truck shall be capable of holding the truck on the maximum grade which the truck can negotiate with rated load, or on a 15% grade, whichever is lesser. The parking brake shall be manually or automatically applied and shall remain applied until released by the operator.(2) Tires shall be used as recommended by the truck manufacturer.Mich. Admin. Code R. 408.12134