The A 8 is a significant East-West transit route. Its construction began in March 1934 during Nazi rule as a "Reichsautobahn", the section between Karlsruhe and Salzburg having been completed by the time road works were discontinued in World War II. Although most parts have been modernized and extended since, significant sections remain in their original configuration from the 1930s - 2+2 lanes, no emergency lanes, steep hills and tight curves. In combination with today's traffic this makes the A 8 one of the most crowded and dangerous autobahns in Germany. Especially in winter the slopes of the Black Forest, the Swabian Alb near Aichelberg, as well as the Irschenberg become bottlenecks when heavy trucks traverse the A8 uphill.