Provision Transport Truck
If your Headquarters is the heart of your campaign, then Supply Convoys are your life-blood. A Supply Depot will dispatch three of these trucks, each carrying $3 ($6 in Nuclear Mode) of resources, to the nearest headquarters by way of the shortest road. During that time, they are completely defenseless against enemy attack, and will usually succumb to even the weakest of armed units. Because of this, it is imperative that you ensure that both your Supply Depots, and the routes between them and Headquarters are completely safe.