The county commissioners may appoint county transport and custody officers, consisting of selected members of the county department of corrections line personnel identified by the superintendent, for the purpose of patrolling county department of corrections buildings, roads, and grounds, and providing for general security at the county correctional facility. If transport and custody officers are appointed, the county commissioners shall adopt a written policy establishing rules relating to the control and responsibility of the transport and custody officers. The policy shall include a requirement for training designed for the specific functions of the transport and custody officers as prescribed in this subdivision, including education on the power of arrest, firearms training and certification, and defensive driving.