The RAD was classed as Wehrmachtgefolge (lit. Armed Forces Auxiliaries). Auxiliary forces with this status while not a part of the Armed Forces themselves, provided such vital support that they were given protection under the Geneva Convention. Some, including the RAD, were militarised.

During the early war Norwegian and Western campaigns, hundreds of RAD units were engaged in supplying frontline troops with food and ammunition, repairing damaged roads and constructing and repairing airstrips. Throughout the course of the war, the RAD were involved in many projects. The RAD units constructed coastal fortifications (many RAD men worked on the Atlantic Wall), laid minefields, manned fortifications, and even helped guard vital locations and prisoners.

The role of the RAD was not limited to purely combat support roles. Hundreds of RAD units received training as anti-aircraft units and were deployed as RAD Flak Batteries. Several RAD units also saw ground combat on the eastern front as infantry. As the German defences crumbled, more and more RAD men were committed to combat. In the final months of the war RAD men formed 6 major frontline units, which saw heavy fighting.