On this trip, I drove from Sibenik to Dubrovnik. The good news is that you have a choice between a scenic route and a very scenic route. The bad news is that driving from Split to Dubrovnik still takes about three hours because the new coastal motorway is not yet finished. Also tabled because of the economic situation is the planned Peljesac bridge which was to have eliminated the need to travel through Bosnian territory at Neum.
Even though the motorway that runs southeast from Zadar stops at around Ravca, well short of Dubrovnik, the fact that it exists has relieved pressure on the very scenic coastal road. Not that the motorway is an ugly route! As it winds through the coastal mountains, the motorway offers some stunning scenery. The Dinaric mountain range that is relatively dry and barren on the seaward side is lush and green on the landward side.
I thought I would save time by getting on the motorway at Ravca rather than driving the coastal road to Split but the two-lane road to the motorway chewed up so much time that there was nearly no difference at all.
Driving down the coast to Dubrovnik, I would advise checking your gas gage before leaving Neum as there are no service stations from Neum to Dubrovnik. Come to think of it, fill ‘er up before getting on the motorway as well. Not all of the planned service stations have opened.
See more on driving in Croatia.
See a road map of Croatia.