Baustelle means road works
Construction zones are common because heavily used Autobahns require continual maintenance and upgrading. Expect reduced speeds and changing lane layouts.
Temporary lanes can be very narrow
Road works often squeeze several lanes into a reduced width. Pay attention to vehicle-width restrictions and avoid drifting toward neighbouring lanes.
Yellow markings take priority
Temporary yellow road markings used in construction zones override the normal white lane markings. Follow the yellow lines until the work zone ends.
Reduced limits begin before the work area
Speed restrictions are often introduced before narrow lanes or traffic shifts. Slow down early rather than braking sharply at the first barrier.
Construction & closures on the Autobahn
Autobahn maintenance and improvements don't escape the German penchant for obsessiveness. As a result, construction zones (Baustelle) are frequent and widespread. The standard protocol for large projects is a traffic shift, the lanes for both directions are narrowed and crammed onto one side of the Autobahn so that the other side can be worked on in its entirety. Such situations are well-marked with signs and speed limits are usually reduced greatly in these areas.
Congested Autobahn with shoulder open to traffic
In the event that a segment of Autobahn must be closed due to an accident or other emergency, pre-posted provisional detours are ready to guide traffic around the closure. As you exit, look for the U-numbered detour sign on the exit ramp - this denotes the detour route for that exit. Follow the same-numbered route over the secondary roads and you'll eventually arrive at the next downstream entrance ramp. If that entrance is also closed, just follow the next sequential detour number to reach the next entrance after that. However, there is one small gotcha, odd numbers continue in one direction, even numbers in the opposite direction. So if you're following an odd numbered route, be sure to follow the next sequential odd number (and, obviously the same goes for even-numbered routes.) These routes also come in quite handy if your patience runs-out and you want to get around a Stau.
Use other lanes sign
Detour sign
Lane control signals
Traffic may be shifted across the median
Major projects can place lanes from both directions on one carriageway. Expect unusual alignments and stay especially alert at crossover points.
Use the zipper merge when a lane ends
Where lanes merge because of road works, use the available lane up to the merge point and alternate with traffic from the neighbouring lane.
Follow the numbered U detours
If an Autobahn section is closed, pre-signed Umleitung routes can guide you from one exit to a later entrance without improvising a route.
Watch vehicle-width restrictions
Some narrow construction lanes display maximum-width signs. Wider vehicles should use the lane indicated for them rather than forcing through a restricted lane.