 At that time, the French trunk road left of the Rhine not been built, so that traffic would cross into Germany to use the Karlsruhe-Basel Autobahn.To add to the buildup of traffic, the neighbouring German state of Baden-Württemberg has imposed a tax on heavy-goods vehicles using their Autobahnen.Thus, a proportion of the HGVs travelling from north Germany to Switzerland or southern Alsace bypasses the A5 on the Alsace-Baden-Württemberg border and uses the untolled, French A35 instead.