 The A 81 north of Gärtringen was eventually cancelled, leaving a half-finished interchange that is one of the few in Germany that requires traffic to leave from the passing lane.As a result, for consistency, the A 81 took over the A 831's routing up to the "Kreuz Stuttgart" interchange with the A 8, where it heads west (concurrent with the A 8) to rejoin the original route.The 2.3 km of autobahn that remained was initially not signed as the A 831.