The R 15 began in Gera and went through Schleiz, Hof, Wunsiedel and Marktredwitz to Mitterteich.

From Mitterteich, it followed today's route to the connection to the Inntalautobahn near Rosenheim.

Now, the R 15 began in the Bohemian town of Karlsbad and traveled through Falkenau (Sokolov), Eger (Cheb), and Waldsassen to Mitterteich and from then on, the same path as before.

After World War II, the path of the road was changed again.

The B 15 now began in Hof and led over Selb and Marktredwitz to Mitterteich, and then south to the Austrian border as before.