more than 48,000 vehicles to the battle zone during the period 17-26 December, and the XII Corps used only two roads to move 11,000 vehicles in four days over a distance of 100 miles. In contrast to the bitter German experience, the American tactical and supply moves seldom were beset by road stoppages and traffic jams, except, of course, in the initial hours of the German penetration. Although it is manifestly true that the Germans made good intelligence usage of the American radio traffic control net, this was balanced by the speed and certainty with which American transport moved. One may also contrast the tactical availability of the great American supply complex which had been built up east of the Meuse with that prepared by the Germans east of the Rhine River. The German offensive forced the Americans away from the forward truck- heads, with their limited capacity, back on the almost unlimited resources available at railheads. Certainly there was some danger involved in the maintenance of the great supply depots so close to the uncertain battle line. Brig. Gen. Robert M. Littlejohn was ordered on three occasions to evacuate the big depots at Liege, but instead simply brought in more supplies. American supply officers seem to have learned something about logistic flexibility as a result of the pursuit operations across France in the summer of 1944. Finally, the much criticized weight of the American logistic "tail" paid off during the Ardennes, for there always was enough extra transport to meet unusual demands for supply and troop movement.
Despite the decline in the production of liquid fuel during 1944, Hitler was able to amass a POL reserve for the Ardennes offensive which equaled that available to the German armies on the eve of the Allied invasion, and the final figure of the POL allocated to Army Group B was over four million gallons. Using the German measure of one "consumption unit" as the amount of fuel required to move all the vehicles in a formation a distance of sixty-three miles, it may be reckoned that of the five consumption units requested by Model only one and one-half to two were at corps dumps on 16 December; yet there may have been as much as nine or ten consumption units available at railheads near the Rhine River.
The course of the campaign showed at least three errors in German planning. POL distribution failed to move with the same speed as the armored advance. The bad terrain and weather encountered in the Ardennes reduced the mileage gained from a tankful of fuel by one-half. And, finally, the expectation that the spearheads would move in part on captured gasoline was mistakenly optimistic. Army Group B POL consumption reached a peak of close to 2,000 cubic meters on 18 December, but by 23 December the daily usage rate was about half that figure. In other words, the supply of liquid fuel failed to keep pace with the tactical demand.
There are two phases in the history of German liquid fuel supply during the Ardennes campaign-the one before and the one after 23 December when the Allies took to the air over the battle zone. During the first phase the movement of POL was impeded by bad roads and traffic congestion. Vehicles failed or ran out of fuel and were