Route 46: Germany's longest motorway ruin

The Reichsautobahn route between Bad Hersfeld and Würzburg, which was never put into operation, is one of the most striking relics of Nazi transport planning—a major engineering project that began shortly before World War II and was never completed. Today, the route, with its partly monumental remains, bears witness to an ambivalent chapter in German history.
Route 46 was planned as a roughly 70-kilometer-long north-south connection through the southern Rhön and Spessart mountains. The route was ideologically exaggerated: the focus was less on traffic efficiency than on landscape aesthetics and propaganda. The planned route was intended to serve so-called "automobile touring" and reveal to drivers "the beauty of the German homeland" – a typical manifestation of Nazi construction ideology.
Initial surveying and construction work began as early as 1937. The project extended from Seifriedsburg in Bavaria (Main-Spessart district) to Bad Hersfeld in Hesse. The route was to run over the Rhön mountain range and along the Saale River in Franconia, with some sections featuring specific views of scenic features such as the Homburg Castle ruins.
Work on Line 46 began with a large deployment of personnel and machinery. Up to 4,500 workers were employed directly on the construction sites, supported by approximately 4,000 additional employees in subcontracting companies. Modern construction equipment of the time was used: steam and diesel locomotives, excavators, dump trucks, and tracked vehicles.
Construction focused primarily on bridges, dams, drainage systems, and underpasses. By the fall of 1939, approximately 30 kilometers of the planned route had been largely completed in shell form, often lacking only the surface course. A total of 47 structures were built, many of which are still visible today.
With the outbreak of World War II in September 1939, highway construction was halted in favor of military priorities. Construction was officially halted on October 4, 1939. The route remained unused, and many materials were removed or looted, partly by the US Army and partly by the population.
The route begins in Seifriedsburg in Lower Franconia and ends at Rupboden near the Bavarian-Hessian border.
Particularly striking is the high bridge pier near Schonderfeld on the Franconian Saale River, which is considered a landmark of the route. Other structures exhibit typical construction techniques of the 1930s, including arched passageways with natural stone cladding and elaborately masonry tunnel tubes. The technical design follows the standards of the Reichsautobahn construction, but with gradients of up to 6.25 percent, which are unacceptably steep by today's standards.
After 1945, the resumption of construction was discussed several times, but ultimately rejected. The decisive reasons were:
- The outdated route with too tight radii and steep gradients
- Changed transport policy priorities of the young Federal Republic
- The route through the territory of the US occupation zone
- The later planning of the A 7 about 20 kilometers further east
Instead of reactivating route 46, the A7 was built in the 1960s as a more efficient north-south axis through Hesse and northern Bavaria.
Route 46 has been a listed monument since 2003. It is considered the longest continuous stretch of a never-used motorway in Europe. Individual sections are now accessible to hikers, and information panels have been installed at prominent points. Local groups regularly offer guided tours explaining the structural remains.
Individual initiatives are striving to preserve and communicate the historical significance of the route, also with regard to the ideological background of its creation.
Despite more than eight decades of service, the structures remain largely intact. The motorway route has become integrated into the landscape, partly as a biotope, partly as a hiking trail. Its documentary value lies in its structural design, but also in the ideological objectives of the Nazi regime. Route 46 thus exemplifies the tension between technological modernity, totalitarian planning, and the culture of historical remembrance.
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