Autobahn - Construction

Construction

Similar to such motorways in other countries, autobahns have multiple lanes of traffic in each direction, separated by a central barrier with grade-separated junctions and access restricted to motor vehicles with a top speed of more than 60 km/h (37 mph). The earliest carriageways were flanked by shoulders about 60 centimetres (24 in) in width, constructed of varying materials; right-hand shoulders on many autobahns were later retrofitted to 120 centimetres (47 in) in width when it was realised cars needed the additional space to pull off the autobahn safely. In the postwar years, a thicker asphaltic concrete cross-section with full paved hard shoulders came into general use. The top design speed was approximately 160 km/h (99 mph) in flat country but lower design speeds could be used in hilly or mountainous terrain. A flat-country autobahn, which was constructed to meet standards during the Nazi period, could support the speed of up to 150 km/h (93 mph) on curves. The current autobahn numbering system in use in Germany was introduced in 1974. All autobahns are named by using the capital letter A, which simply stands for "Autobahn" followed by a blank and a number (for example A 8). The main autobahns going all across Germany have a single digit number. Shorter autobahns that are of regional importance (e.g. connecting two major cities or regions within Germany) have a double digit number (e.g. A 24, connecting Berlin and Hamburg). The system is as follows:

• A 10 to A 19 are in eastern Germany (Berlin, Saxony-Anhalt, parts of Saxony and Brandenburg)
• A 20 to A 29 are in northern and northeastern Germany
• A 30 to A 39 are in Lower Saxony (northwestern Germany)
• A 40 to A 49 are in the Rhine-Ruhr Area
• A 50 to A 59 are also in the Rhine-Ruhr Area
• A 60 to A 69 are in Rhineland-Palatinate, Saarland and Hesse
• A 70 to A 79 are in Thuringia, northern Bavaria and parts of Saxony
• A 80 to A 89 are in Baden-Württemberg
• A 90 to A 99 are in (southern) Bavaria

There are also very short autobahns built just for local traffic (e.g. ring roads or the A 555 from Cologne to Bonn) that usually have three digits for numbering. The first one of which is similar to the system above, depending on the region. East-west routes are always even-numbered, north-south routes are always odd-numbered.

The north-south autobahns are generally numbered using odd numbers from west to east; that is to say, the more easterly roads are given higher numbers. Similarly, the east-west routes are numbered using even numbers from north (lower numbers) to south (higher numbers).