№ 1 is Russia's P-21 at 1,471 km, from St. Petersburg north to the Russia/Norway border.
№ 2 is Russia's P-22 motorway at 1143 km from outside Moscow south towards the Caucaus
№ 3 is Germany's A 7 north-south motorway at 961 km.
№ 4 is Norway's part of the E 6 at 952 km (this shows complexities with OSM tagging. the E 6 is v. large.)