The following is an expanded version of material in "The Man Who Changed America."
Although the 1919 convoy shaped Eisenhower's views, his perspective would be supplemented years later by his observations of the German autobahn network of freeways.
Plans for the autobahn date to the 1920's. Construction of the first segment (Cologne-Bonn) began in 1929 and was dedicated by Mayor Konrad Adenauer of Cologne on August 6, 1932. When Adolph Hitler assumed power as Chancellor of the Third Reich in 1933, he took the program over, claiming it for his own. "We are setting up a program," he said later that year, "the execution of which we do not want to leave to posterity."
Hitler's autobahn construction began in September 1933 under the direction of chief engineer Fritz Todt. The 14-mile expressway between Frankfurt and Darmstadt, which opened on May 19, 1935, was the first section completed under Hitler. By December 1941, when wartime needs brought construction to a halt, Germany had completed 2,400 miles (3,860 km), with another 1,550 miles (2,500 km) under construction.
As many American visitors had noted during the 1930's, the autobahn was built before the country had enough motor vehicles to justify the expense. Only the well off or powerful in Germany could afford automobiles. Hitler had highlighted this problem in a speech on March 3, 1934, at the Berlin International Automobile and Motor Cycle Show:
It can only be said with profound sadness that, in the present age of civilization, the ordinary hard-working citizen is still unable to afford a car, a means of up-to-date transport and a source of enjoyment in the leisure hours. One must have courage to face problems and what cannot be solved within one year may become an established fact within ten years . . . .
Hitler intended to provide a small affordable "people's car" (Volkswagen) that his people could fill the autobahn with.
Dr. Ferdinand Porsche completed design of the vehicle in 1938. That autumn, the Nazi Party Labor Organization completed some of the construction on the assembly plant at Wolfsburg. In Hitler's full-employment economy, however, construction was delayed by the absence of workers. Benito Mussolini of Italy immediately provided 1,000 unemployed workers to Wolfsburg at Hitler's request, and more as needed.
Over 360,000 Germans paid in full or in installments for the vehicle in advance of its production. However, in August 1939, Hitler ordered Dr. Porsche to switch the Wolfsburg plant to production of military vehicles based on the Volkswagen. With Czechoslovakia and Austria under German domination and troops ready to move into Poland, the military would have to take priority.
In the end, none of the purchasers received a Volkswagen-or refunds as war needs dominated the country. (For information on the history of the Volkswagen before and after World War II, see Phil Patton's Bug: The Strange Mutations of the World's Most Famous Automobile, Simon & Schuster, 2002.)
At the outset of World War II in Europe, the autobahn proved to be a key asset to Germany. The German blitzkrieg ("lightning war"), which involved massive coordinated air and ground attacks to stun opponents into defeat, was a key to the German defeat of Poland in 1939, Belgium, Luxembourg, and the Netherlands in 1940, and the Soviet Army in 1941. The highway network also enhanced Germany's ability to fight on two fronts-Europe in the west, the Soviet Union in the east.
Germany, despite these early advantages, had initiated the war before it had the industrial base to support its military over time. The absence of plants that could be converted to military production was one of the fatal flaws of the German war effort. As historian David P. Colley explained (in The Road to Victory: The Untold Story of World War II's Red Ball Express, Brasseys, Inc., 2000), "The bulk of the German Army of World War II was largely supplied by wagon trains, even to the end, and its infantry marched or rode trains or even used bicycles." He adds that Germany employed 2.8 million horses during the war to support its mechanized divisions.
Once the United States entered the war in December 1941, the German deficiency was accentuated because America had the industrial base to create what Colley calls "the world's most highly mobile and mechanized force." The "secret weapon," as Colley called it, was the truck. America produced 3 million trucks or truck-type vehicles for the war. With the French rail network devastated by air attacks prior to the allied D-Day invasion on June 6, 1944, the trucks, often operated by the black troops of the Red Ball Express, were the key to supplying the troops as they advanced through the French countryside.
By the time the Allied forces reached Germany, they could take full advantage of the autobahn. E. F. Koch, a U.S. Public Roads Administration (PRA) employee who observed the autobahn in 1944-45 as a highway and bridge engineer with the Ninth Army. He and his engineering unit spent the unusually cold winter maintaining roads in Belgium, Luxembourg, and the Netherlands that, after the pounding of military vehicles and the thaw in early 1945, were in terrible shape. Conditions changed when they reached Germany in early 1945. "After crossing the Rhine and getting into the areas of Germany served by the Autobahn . . . our maintenance difficulties were over. Nearly all through traffic used the Autobahn and no maintenance on that system was required."
As the Allies pursued the German forces across Germany, the autobahn proved invaluable, especially to the supply trucks racing behind the troops. The supply units and their vehicles, which had been run ragged in France, strained to keep up. Colley quotes Corporal Edwin Brice of the 3909th Quartermaster Truck Company (I Company) who observed on March 26, 1945, that the unit's trucks had "taken an awful beating across France," but added that "victory depends on our success in keeping troops and supplies up where they are needed. If a truck or a driver can move he or it is needed."
In the immediate aftermath of the war, Eisenhower was the military head of occupied Germany. Writer Phil Patton pointed out in Open Road that in this capacity, "Eisenhower oversaw the 'debriefing' of the Reich, the creation of a series of reports that included close study of the Autobahns."
The autobahn was a rural network, without segments into and through Germany's cities. This seemed appropriate to Eisenhower, but in Washington, Thomas H. MacDonald and Herbert Fairbank of the U.S. Public Roads Administration (the name of the Federal Highway Administration's predecessor during the 1940's) saw the absence of metropolitan segments as a flaw that made the autobahn a poor model for America's future. Unlike Germany, traffic volumes were high in America where car ownership was widespread. Congestion in America's cities had long been a serious complaint that MacDonald and Fairbank would address in their vision of the Interstate System. (For information, see "The Genie in the Bottle")
In short, where Germany had intended to build the highways first and the vehicles second, America had the vehicles and no clear plan for building the highway network.
For Eisenhower, the vision of the autobahn was strong in his mind as he became President. Years later, he would explain that "after seeing the autobahns of modern Germany and knowing the asset those highways were to the Germans, I decided, as President, to put an emphasis on this kind of road building. ... The old  convoy had started me thinking about good, two-lane highways, but Germany had made me see the wisdom of broader ribbons across the land."