Bundesstraße
One distinguishing characteristic between German "Bundesstraßen" and "Autobahnen" is that there usually is a general 100 km/h (62 mph) speed limit on federal highways out of built-up areas, as opposed to the merely advisory speed limit ("Richtgeschwindigkeit") of 130 km/h (83 mph) in unmarked sections of the autobahns. However, a number of "Bundesstraßen" have been extended as expressways (dual carriageways) (colloquially called "Yellow Autobahns"). Many of these have speed limits of usually 100–120 km/h, others have only an advisory speed limit like autobahns. Most sections of the federal highways are only single carriageway with one lane for each direction and no hard shoulder pull-out area.
Bundesautobahn 99
The Aubinger Tunnel is Bavaria's longest motorway tunnel with its 1956 meters. It has been honored by the ADAC as one of the safest tunnels. The tunnel also has one of the most modern speed control systems in Europe. The measurements have been made in both directions since the beginning of March 2008, without the drivers noticing. Every 500 meters after the entrance, measuring points are set up in both directions, which forward the measured data directly to the police. In the first week after its launch, more than 1,500 speeding violations have been registered, according to press releases.