Reichsautobahnen in the Nazi era: planning, ambition and failure

Planning and construction activities reached their peak between 1937 and 1939. During this period, work also began on the five later unfinished routes. What they had in common was that they mostly only reached a certain shell stage before being halted with the outbreak of war on September 1, 1939. Labor and materials were diverted from road construction and diverted to the armaments industry. These projects were never resumed after 1945—partly because many routes were cut through by the German-German border or were considered technically obsolete.

Route 85 was planned as a fast connection between Eisenach, Meiningen, and Bamberg, shortening a central north-south axis between Hamburg and Munich. The planned length was approximately 150 kilometers. The route would have connected numerous medium-sized towns to the motorway network for the first time, including Meiningen, Schmalkalden, and Coburg.

Construction work began on several sections in 1938. The area between Breitungen and Niederschmalkalden was particularly advanced, with a roughly ten-kilometer-long section already equipped with a base course and structures. There, the route had already been laid across its entire width – including underpasses and dams. Further remnants can be found near Wutha-Farnroda, where the abutments of the planned Kirchtal Bridge have been preserved.

The outbreak of war led to an immediate halt to construction here as well. The location on what would later become the inner-German border made continuation after 1945 impossible. Part of the route was integrated into Federal Highway 19 in the 1950s. It is still clearly visible today in Breitungen, Niederschmalkalden, and Barchfeld. Efficient alternatives later emerged, albeit with different routes, with the A 71 (Erfurt–Schweinfurt) and A 73 (Suhl–Coburg–Bamberg).

In Saxony-Anhalt, too, construction began in 1939 on a new Reichsautobahn (Reichsautobahn) to connect Magdeburg with Halle. The approximately 100-kilometer-long route was part of a larger plan to better connect Central Germany to the Autobahn network and create an alternative north-south connection away from Berlin.

Starting in spring 1939, approximately 18 kilometers of work began on the line between Halle-Peißen and Löbejün. Earthworks costing millions were carried out, and the first bridge foundations were concreted. The route was particularly complex in the Saale Valley area. However, construction was halted in the fall of 1939 before a continuous section had been completed.

In the decades following the war, some fragments remained visible—for example, near Rothenburg or along the later A 14 route. These remnants were not a priority during the GDR era; after reunification, they were replaced or built over by modern road construction projects. Today's A 14 largely follows the originally planned route.

Route 71 was a particularly ambitious project. It was intended to serve as a cross-connection from Göttingen via Nordhausen and Sangerhausen to Dessau, south of the Harz Mountains. The planned length was approximately 186 kilometers. The technical centerpiece was to be a monumental arched bridge near Rothenburg an der Saale – designed by Paul Bonatz , with a length of 670 meters and a height of 56 meters. It would have been used simultaneously by two Reichsautobahns (routes 71 and 23).

In 1938, routing work and the first excavations began. However, the debate about the shared use of the Saale Bridge delayed the start, and construction was halted in November 1939, even before any buildings were erected. The project was not pursued further during the GDR era.

The idea of ​​an east-west connection in the southern Harz region was only realized in the 2000s with the construction of the A 38. Today, this largely follows the planned route of route 71 – with a modern alignment and modified crossings. However, the historic Saale Bridge was never built.

Paul Bonatz (1877–1956) was a German architect and civil engineer who, as a representative of conservative modernism, designed numerous bridges, train stations, and administrative buildings. His most famous work is Stuttgart Central Station, which he built between 1914 and 1928 with a clear, functional design language. In the 1930s, Bonatz was also involved in the design of the Reichsautobahn (Reichsautobahn), including the design of a monumental bridge over the Saale River near Rothenburg. Due to increasing conflicts with Nazi construction policy, he went into exile in Turkey in 1943. After returning to Germany in 1954, he died in Stuttgart two years later.

Route 24 was a northern German subproject and was planned as a continuation of the Hamburg–Frankfurt long-distance line (HaFraBa). The section through Wedemark near Hanover was to be approximately 35 kilometers long. It ran through marshy terrain north of the city and presented significant engineering challenges.

Starting in 1938, the first dams were built, drainage ditches were dug, and individual bridge fragments were erected. However, progress was limited, not least due to poor soil conditions. Here, too, construction finally came to a halt in 1940.

After the war, the A7 motorway—as the most important north-south connection—was built further west. The route of Route 24 fell into oblivion. Today, some dams and pillar remnants can still be seen in the Wedemark region near Resse. An educational trail provides information about the history of the unfinished motorway and the area's moorland ecology.

Route 46 is the most famous example of an unfinished motorway in Germany. It was originally intended to create a north-south connection between Fulda in Hesse and Würzburg in Bavaria, crossing the Rhön and Spessart mountains. Unlike the later A7, this route was strongly motivated by landscape aesthetics: Numerous vantage points were integrated into the route, including views of the Homburg Castle ruins.

Construction began in 1937 and progressed rapidly until 1939. A total of 47 structures were erected in shell form over a distance of approximately 30 kilometers – including underpasses, bridge piers, massive dams, and arched passages with natural stone cladding. In some cases, only the road surface was missing. The most famous structure is the massive bridge pier near Schonderfeld, which still stands as a landmark over the valley of the Franconian Saale River.

After the outbreak of war, all work was suspended. A resumption after 1945 was never seriously planned. Instead, the A7 was built significantly further west – with a flatter route and better connections to Schweinfurt. The remains of route 46 are largely preserved today and have been a listed monument since 2003. Hiking trails run along the old route, and information panels have been erected at several locations. The route is considered the longest historic engineering monument of its kind in Germany.

All five motorway projects were discontinued between 1939 and 1940. The reasons are varied, but they can be summarized in four groups: