Complex sentence: The D21 route is generally parallel to the A9 motorway and the two form several junctions, either directly or via short connectors, while serving the towns of Buje, Bale and Vodnjan directly.
Split into simpler sentences: The D21 route is generally parallel to the A9 motorway. The two form several junctions, either directly or via short connectors, while serving the towns of Buje, Bale and Vodnjan directly.