I also like to ask, how exactly did the carriage system in Morrowind differ from Oblivon in terms of danger? You still got from A to B instantly, no danger involved (except getting to that ride, of course. If Bethesda can make the Carriage system interactive, then that'd be an incredibly good feature. It could be something like the Gryphons in WoW, except that random encounters could sometimes stop you in your tracks (rarely, but still). Then you'd have to defeat that encounter and enter the carriage once again, and head off to your destination.
But I doubt that this is how carriage works. It's as instant and magical as the map.
I believe it will be more like RDR carriage system. where a horse drawn carriage will take you to your destination and you can choose to skip it if you want (i like to think i take a nap).
like i said before, there's a difference between going on a commercial road, and fast-traveling 2 miles into a deep forest densely populated by monsters. It just seems like a better justification for not having to battle monsters to me if you take the commercial road.
that being said, i would love it if on either "magic map" or "carriage" fast travel you could be ambushed.