 The A 643 begins at the Dotzheim Interchange in Wiesbaden as a continuation of Schiersteiner Straße (Bundesstraße 262) to and from the city center (alternatively, southbound traffic on Schiersteiner Straße can continue on Saarstraße/"Kreisstraße" 645 to Schierstein).This interchange also includes an exit ramp to Erich-Ollenhauser Straße (K 655), which leads northwest to Wiesbaden-Dotzheim and southeast to Biebrich.The A 643 soon intersects with the A 66 at Schiersteiner Kreuz.