|Length:||529 km (329 mi)|
|States:||Brandenburg, Saxony-Anhalt, Saxony, Thuringia, Bavaria|
The southern terminus of the A 9 is in the district of Schwabing in Munich. In the north at the Potsdam interchange it merges into the A 10, also known the "Berliner Ring", 30 km away from Berlin city limits. The shortest route from there into Berlin would be the A 10 (east) and the A 115. On its way, the A 9 passes through Bavaria, Thuringia, Saxony-Anhalt, and Brandenburg. To the west of Leipzig, the border between Saxony-Anhalt and Saxony crisscrosses along the autobahn.
The A 9 was originally built as part of the Reichsautobahn system under the Third Reich. It was inaugurated in sections, beginning in 1936 with the part between what is today's Schkeuditz interchange (A 9 and A 14) and Bad Berneck, 164 km in length. In 1941, the second lane near Schnaittach was the last gap closed. This makes the A 9 one of Germany's oldest interregional autobahns. Until the introduction of a new numbering system in 1974, it was the A 3.
It served as one of three transit access roads through the GDR toward West Berlin during the Cold War. Yellow signs with "TRANSIT" in black letters marked the allowed route. Distances were usually given towards "Berlin - Hauptstadt der DDR" (Berlin - Capital of the GDR), not Berlin (West). Despite funding from West Germany, road conditions were generally poor. The surface was concrete slabs rather than blacktop or continuously cast concrete. A section in Thuringia between Schleiz and Rodaborn had cobblestones, which were later paved over by the GDR until being replaced by concrete in the 1980s.
Between 1945 and 1966 the A 9 was interrupted at the border between Bavaria and Thuringia (the then inner German border) since the bridge over the river Saale had been destroyed near the end of World War II. Traffic to and from West Berlin was diverted via A 72 until 1951 and from then until 1966 via B 2.
After German reunification, the A 9 was to be rebuilt and upgraded, being German Unity Transport Project No. 12. The old two-lane profile without emergency lane was in no way suited to modern levels of traffic, speed, and expected safety. In 1990, 50,000 vehicles per day were counted near Bayreuth, about as much as the motorway could handle. After the work was finished near Bayreuth in 2006, the only part of the old profile is in Thuringia between Schleiz and Triptis. Planning for this is in progress, as it is the last bottleneck on the A 9. Once this construction is finished, there will be at least three lanes plus emergency lane in each direction for the whole route.
On June 30, 2004, Germany's oldest autobahn inn, Rodaborn, near Triptis, was closed due to the upgrading of the old two-lane to the modern three-lane profile. Rodaborn was opened in 1928 as a country inn for the local population and turned into a rest area in 1936 when the autobahn was opened. During the days of the GDR, it was open only for transit travellers, not for the people of the GDR. In a loop of history, in 2009 it was rented by a local couple intending to re-open it as an inn for local daytrippers.
Current condition and future plans 
With two exceptions, the A 9 has a profile of three lanes and one emergency lane per direction. Exceptions are a 19 km stretch in Thuringia, and the part between Munich-Nord and Neufahrn, north of Munich, which has been upgraded to four lanes each way. This part was surveyed in 2008 with an average number of 143,000 vehicles per day with a maximum of 184,000.
Since 2006 talks have started about turning the three-way interchange Holledau into a four-way, and extending the A 93 into the Pfaffenhofen area.
Further plans and visions include widening to six lanes between Triptis and Schleiz in Thuringia, and to eight lanes between interchanges Nuremberg and Nuremberg-East, and Holledau and Neufahrn, respectively.
Along the route 
Close to exit 10, Dessau-East, a gravel pit had provided material for the construction of the autobahn. After 1939 the pit was renaturated and became the "Reichsautobahnbad Mildensee", with cabins to change, and eateries. It is still in use today as a beach, but not under the old name.
South of exit 11, Dessau-South, nearly ten kilometers of the roadbed — roughly from Thurland southwards to just north of the B 183 interchange (exit 12 for Bitterfeld/Wolfen of the modern A9 roadbed) — were upgraded with a paved-over median to become the "Dessauer Rennstrecke" (Dessau Racetrack), a 25 meter (82 ft) wide high-speed track intended for races and record attempts, such as those to be attempted by the Mercedes-Benz T80 land speed record car starting in January 1940. With its pillarless bridges, but especially with the straight alignment and the broad concrete surface without a distinct median, it was also intended to function as an auxiliary airfield in WWII.
The four-way interchange at Schkeuditz was the first cloverleaf interchange in Germany, as well as the first autobahn interchange in Europe. It was opened in 1936, two years before construction was finished.
The Frankenwald rest area near exit Rudolphstein is one of two rest areas in Germany with a restaurant bridging the road.
In Lanzendorf near Bad Berneck, the autobahn passed right through the village on a bridge. The route was realigned during the construction after 1990. Right next to the old route, the autobahn church Lanzendorf was built. Sanctification took place October 6, 1996.
Exit 40b, Bindlacher Berg, was until after reunification no public exit, but used exclusively by the US Forces stationed on the Bindlacher Berg.
Until the upgrade to six lanes, from Bayreuth-Nord to Bindlach existed the last autobahn alley of trees in Germany. It has been replanted since.
Near Trockau, the former steep and curvy section also was realigned after 1990.
Exit 45, Weidensees, was called "Veldensteiner Forst" until the 1970s and was probably built on behalf of Hermann Göring, who had a hunt nearby. Weidensees itself did not merit its own exit.
Interchange 51, Nuremberg, was originally a cloverleaf. It had been improved by adding a long, sweeping bridge from the northern lane of the A9 coming from Munich towards the A3 in the direction of Würzburg and Frankfurt, since the traffic in that direction was much heavier than the traffic heading north. The old, small curve in the former south-east quadrant still shows what is probably the original 1930's cobblestone.
Despite the upgrade to six lanes total, some original bridges have been retained, but carry just one direction, like the bridge crossing the Saale at the old border crossing between Bavaria and Thuringia.
From 2000 until construction began to upgrade to four lanes for each direction, the section between Neufahrn and Munich-Nord was among the first in Germany where it was allowed in appropriately heavy (and correspondingly slow) traffic to legally use the emergency lane as an additional traffic lane. Since further adding of two more lanes north of Neufahrn towards Holledau is not in sight, a similar regulation is considered for this section.
Near exit 73, München-Fröttmaning, there's a Berlin Bear statue placed on the median (checkpoint Bravo .). Its equivalent is placed on the median of the A 115 (as the extension of the A 9 into Berlin) near former rest area Dreilinden, north of the former
At the entrance to the rest area "Köschinger Forst", direction Berlin, there's a milestone with the inscription Berlin - 500 km.
Culture References 
- Spider Murphy Gang song FFB is about a car accident between Nuremberg and Ingolstadt.
- Geographic data related to Bundesautobahn 9 at OpenStreetMap
- Bundesautobahn 9 – Detailed route plan (German)