The first plans for the northern section between Emmerich and Oberhausen, the so-called "Holland line" (Reichsautobahnstrecke 92), date to 1936. Despite difficulties in the route definition (industrial areas in Oberhausen and Dinslaken are crossed) was already in July 1939 with the construction to be started. Because of the Second World War, the construction work had to be stopped that October until July 1940. . Up to about a third of the earthworks were completed. The route was already cleared and construction had started on 29 buildings. The first plans for the Cologne-Düsseldorf route go back to 1925. In 1929 the Provincial Association of the Prussian Rhine Province legally established the route between Cologne-Düsseldorf and in 1931 the construction started of a 2.5-kilometer section at Opladen. It was opened on 27 September 1933 and shortened the section of trunk road 8 between the two cities. The southern part of this route was not further upgraded and included in a simple bypass, now part of the B 8 / L 288 (Bonner road). In the years up to 1940, the rest of the Reichsautobahn Oberhausen (following the A 2) was built over Cologne to Wiesbaden sections. The 25-kilometer section from Cologne-Mülheim to Mettmann was opened on 21 May 1936 to traffic. In the same year, the section from Breitscheid to Oberhausen-Lirich / Duisburg-Meiderich was completed in the northerly direction. In 1937, the northern continuation of the current motorway junction Oberhausen and the gap closure between Mettmann and Breitscheid followed. The southern route allowed the direction Reichsautobahnen simultaneously from both Cologne in the south and Wiesbaden in the north. The section between the interchange Köln-Mülheim and Siegburg 30 km in length was handed over on 17 December 1937 after about three years of construction time traffic. One year later, on 15 December 1938, the 12 km section was taken to the junction Siebengebirge and on 20 September 1939 followed by another 30 km to Dierdorf. The southern section with 48 km length between the former junction Wiesbaden, today's Wiesbadener Kreuz, and the junction Limburg-Nord was opened on 23 September 1939 traffic. The most elaborate structure in this section was the then approximately 500 m long and 60 m high Lahntalbrücke. The 41.5 km long gap between Limburg and Dierdorf took place on 15 June 1940. The construction of the section south of the Wiesbadener cross with the Main Bridge between Raunheim and Eddersheim was started in 1938, but had to be discontinued in early 1943. The section from Erlangen to the Nuremberg junction was completed in 1941, partly in one lane. In 1937, planning for the motorway section from Nuremberg via Regensburg to Passau was begun. In the area between Nuremberg and Oberpfraundorf, however, a different route was chosen than the later built. The original route led over the area of the enlarged military training area Hohenfels after the Second World War. Also, in contrast to today running south of the city A 3 Deggendorf north should be bypassed. After 1939 already in some sections on the Franconian Alb and Wörth on the Danube and Deggendorf with earthworks and bridge construction work was started, they stopped the work, as on the northern section, 1942 due to the war. In the course of this work, the construction of a Danube bridge near Regensburg was started. After the war, in 1958 with the continuation of construction of the line Emmerich-Oberhausen ("Holland Line") started. In 1961, the 17.5 km long section from the cross Oberhausen to Wesel was completed. Already two years earlier, in 1959, the construction of the "Zubringers Oberhausen" as the southern extension of the road to the B 223 (today's A 516) began. Also the 7.2 km long section between the border crossing Elten and Emmerich has already been built. This was then in an area that was still under Dutch administration until 1962, the construction was in collaboration with the Dutch Road Administration. The road cross section, however, corresponded to the German standard. The construction work was completed in 1962 and completed the section. In 1963, both the "Oberhausen connection" south of the Oberhausen cross and the section between Wesel and Hamminkeln were released. The total distance from Oberhausen to the Dutch border was completed in 1965. In June 1950, the construction work on the motorway south of Wiesbaden was resumed. The completion of the 3.5 km section to Weilbach was 1951, the following 17.4 km to Frankfurt-South were inaugurated on 10 July 1956. This was near the Frankfurt Rhein-Main airport for linking with the Federal Highway 5, the Frankfurter Kreuz and thus the first motorway junction in West Germany. The 214 km section from Frankfurt to Erlangen-Tennenlohe was built within nine years. The total cost amounted to about one billion DM. During construction, 21 construction workers were killed. From 15 December 1959, the highway with the maximum four percent steep Spessart climb to Rohrbrunn was passable. The traffic clearance to Würzburg-West followed on 27 October 1961. On the way to the Nuremberg area was gradually built in the next few years. The 42 km long piece of the gap between Rottendorf and Schlüsselfeld was handed over to traffic on 26 November 1964. The line was equipped with a total of 54 rest stops in the direction of Nuremberg and 64 in the direction of Frankfurt as well as four rest stops. Between Aschaffenburg and Würzburg 11 springs and wells were offered to motorists. From Tennenlohe to the cross Nuremberg, the highway was already passable in 1941, but only in the section AS Nuremberg / Behringersdorf to AS Nürnberg-Mögeldorf two lanes. The complete release for this area could take place only 1959. The route was from 19 December 1963 from Nuremberg to Schlüsselfeld passable. After the plans for the motorway section Nuremberg-Regensburg-Passau were resumed in 1958, due to the training area Hohenfels the originally planned and partly built track could not be further developed, they decided on a route through Altorf, Neumarkt and Parsberg, the at Oberpfraundorf again on the prewar road encounters. This could be largely retained in the course. The 25.5 km long section Nittendorf-Rosenhof could be completed as early as 1965, the western adjoining, 25 km long section Parsberg-Nittendorf 1969. In 1971, the A 3 in the direction of Nuremberg was already passable for another 27.6 km to Neumarkt. Since then, the motorway from the Dutch border to the east of Regensburg (junction Rosenhof) was continuously passable. In 1968 the construction of the motorway between Deggendorf and Passau began. The 20 km long section from the motorway intersection Deggendorf to Iggensbach was completed in 1975, followed in 1978 by the subsequent approximately 21 km long route to the junction Passau -Nord and in 1979 another 9 km to Passau-Süd together with the Danube bridge Schalding. In 1983, the motorway section between Passau-South and the Austrian border was completed. Between Regensburg and Deggendorf was only built in the late 1970s to early 1980s. In 1980, the A 3 of Rosenhof was extended by 9 km to Wörth on the Danube, with a further Danube crossing was created (Danube bridge Wörth). In 1981, 20 km were added to Straubing, the gap closure to Deggendorf was opened in 1984. Thus, the highway was completely completed and passable. 1992 was a general reorganization of the motorway network in Germany. As a result, the signage had to be revised, the number of goals on the signposts was reduced, which was partly accompanied by a considerable loss of information. At the same time, a numbering of all junctions, triangles and crosses in the German motorway network was carried out. As part of this reorganization arose by linking the former A 2 section from the Dutch border at Straelen to Duisburg with the former A 430 Duisburg-Kaiserberg-Dortmund the A 40. The double designation "A 2 / A 3" for the hitherto common Motorway section from the cross Duisburg-Kaiserberg to the cross Oberhausen could thus be reduced to A 3. At the same time, the junctions of this along the city limits Duisburg / Oberhausen running part of the motorway were renamed. The junction Duisburg-Meiderich received the new name "Oberhausen-Lirich", the cross Duisburg / Oberhausen, which is located entirely on Duisburg city, the new name "Cross Oberhausen-West" and the junction Duisburg-Hamborn the new name "Oberhausen- Holten ". The name for the cross Duisburg-Kaiserberg has been corrected in "Kreuz Kaiserberg". The reference to the destination Duisburg along the A 3 from the cross Hilden in the north was deleted. Since then, there is such a hint only on the cross Breitscheid. The two connection points on Leverkusen city area were renamed in 2009. Thus, the AS 22 (Leverkusen-Opladen) was formerly called only "Opladen" and the AS 24 (Leverkusen-Zentrum) only "Leverkusen". The basis for this was a decree of the North Rhine-Westphalian Ministry of Transport (so-called "large city regulation"), which states that in connection with cities with more than 100,000 inhabitants, the city name must be prioritized. The A 3 runs parallel to the
Bundesstraße 8, which it thus replaced as a main highway. Both follow the medieval trade route
Via Publica that was first mentioned in a document from 839. From 2006 to 2008, the section between the junctions Aschaffenburg and Aschaffenburg-Ost was expanded to six lanes. A fatal accident occurred on 23 October 2006, when a World War II aerial bomb exploded while milling a cement-lime mixture in the new hard shoulder. A construction worker was killed, the milling machine was completely destroyed and several vehicles and buildings were damaged. During a subsequent unearned dupe search in the peripheral areas and at greater depths, even more duds were found. In a highway renewal work in the summer of 2014, a 500 kg heavy bomb from the
Second World War was found on 19 August between the Offenbacher Kreuz and the junction Obertshausen. For defusing the A 3 between the Offenbacher cross and the junction Obertshausen was closed in both directions. Since it was not possible to remove the detonator of the British dud, the bomb had to be blown up on site. The result was a crater with dimensions of about 10 × 5 meters and a depth of about 3 meters. Furthermore, the road superstructure of the first lane and the stationary strip of the directional road raised up to about half a meter. The road to Würzburg was closed until 21 August. == Current state ==