For decades, there have been wranglings over a 42.5 km extension of the A 49 from Neuental southwards to ease traffic on the A 7 and better serve the cities of Kassel and Marburg towards the Rhein-Main Region.

[1] The German branch of Friends of the Earth filed a suit against the planned extension in January 2008 before the Federal Administrative Court in Leipzig.

The A 49 was originally supposed to follow a different course: from Kassel past Fritzlar, Schwalmstadt, Stadtallendorf, Kirchhain and Marburg to Gießen.

From Preungesheimer Dreieck, the A 49 would have followed the route of the current A 661 past Offenbach am Main and Egelsbach to Darmstadt, where it was supposed to end at A 5 south of the city.

Several sections of the original A 49 have been constructed with different names: the four-lane section of Federal road 3 between Marburg and the Gießen North interchange, between Karben and the Preungesheimer Dreieck, Bundesautobahn 485 between the Gießener Nordkreuz and Butzbach, and Bundesautobahn 661 between the Preungesheimer Dreieck and Egelsbach.