Why does the Military Surface Deployment and Distribution Command administer highways for national defense?

The Military Surface Deployment and Distribution Command (SDDC) administers specific public and private highways because the Department of Defense deems these routes to be of major transportation importance to national defense.1

As an Army Service Component Command, the SDDC is responsible for the global movement of military cargo, combat units, and personnel. By overseeing these critical transportation networks, the command ensures that the military maintains the capability to mobilize forces and transport essential supplies efficiently during both peace and wartime operations. This oversight is a key component of the SDDC's broader mission to manage the movement of freight and passengers for the Department of Defense.12