Bundesautobahn

Autobahn (German, word translation car [rail] way) is the controlled-access highway system in Germany.
They are famous because if there is no speed limit shown with road signs, drivers can drive as fast as they want to if following the general rule of due care. About 30 % of all autobahn sections have a speed limit.
Design
An autobahn is designed for fast travel.
Curves are very large.
Slopes are not too steep.
There are many tunnels and bridges to avoid curves and big slopes.
The street surface is solid.
There are no traffic lights or (same-height) intersections.
Main road
Except for ramps, an autobahn has at least two lanes in each direction.
Each direction is separated by a median strip.
The median strip usually has a metal barrier.
There are small plants like bushes.
This blocks lights of cars driving in opposite direction.
Sometimes there is a , instead.
Near cities or in other high-traffic areas, there may be more than two lanes for one direction.
Except for very few low-traffic areas, an autobahn has one additional lane that is not for moving traffic, but for vehicles having mechanical failures ().
Except for some city autobahns, there are no streetlights.
Other things
At a German autobahn, every there is an emergency telephone.
The direction of the closest emergency phone is shown by a triangle on the reflector posts.
Junctions between two autobahns are called
if one autobahn ends there or
, an interchange.
Junctions with normal roads are called .
On the autobahn the traffic sign reads .
All junctions of an autobahn are numbered sequentially.
Junctions that were build after the autobahn was completed may have one letter, too.
This prevents giving all other junctions new numbers.
All autobahns have rest stops.
These are parking lots.
Most parking lots also have big space for trucks.
Occasionally the rest stop has a toilet, too.
There are also gas stations.
Frequently, gas station and rest stop are combined, some have a (fast-food) restaurant or even a hotel or church.
Both, rest stops and gas stations, can usually only be accessed from the autobahn, so the area cannot be used as an unofficial .
Law enforcement
The German autobahn has its own police, the .
They have very fast police cars.
There are police stations on the autobahn.
There are no active border checkpoints anymore.
Since the reunification of the Germanies, the German Democratic Republic and Federal Republic of Germany, the Helmstedt-Marienborn border crossing on the A2 has lost its function.
Since the Schengen Agreement there are also no checkpoints to neighboring countries.
Rules
Order
Germany has right-hand traffic.
All drivers are supposed to drive in the outer-most lane.
This is the right-most lane.
Only for moving past other cars or trucks that are going slower the right-most lane may be left.
Speed
It is forbidden to stop on an autobahn, unless there is a situation asking for it (for example a car crash).
It is forbidden to park on an autobahn.
It is forbidden to reverse or turn around, except if the police asks for it.
Pedestrians or bicyclists are not allowed on an autobahn.
All vehicles must by design be able to go faster than .
This is not a minimum speed.
If the situation asks for it, for example a traffic jam or whiteout (very strong snow) condition, a slower speed can be driven.
During the 1973 oil crisis there was a general speed limit of in West Germany.
Because of criticism, four months later the speed limit was removed.
Today, about 50 to 70% of autobahns in Germany have no speed limit shown by a traffic sign.
There is only a speed recommendation of per hour.
The traffic law says, drivers must adjust their speed to the road condition and go only as fast as they can safely stop within the area they can see.
However, if you are involved in an accident while driving faster 130 km/h, you are automatically attributed contributory negligence of about 30%.
Fee
Driving on a German autobahn is free for cars.
Since 2005, trucks (12.5 tons and above) do have to pay a toll of about a twelve cents (EUR0.12) per kilometer.
Discussion about general maximum speed
There have been many discussions about introducing a general speed limit on all German roads.
Some people say it will improve traffic safety.
The German Road Safety Council (DVR) has found that on average there are 25% more deaths on sections of the autobahn without speed limits compared to those with a limit.
Data analysis performed by Der Spiegel has found that a speed limit applied across all German motorways would save 140 lives a year.
In Germany, many cars and trucks use an internal combustion engine.
Some people say a maximum speed was necessary because of the environmental pollution.