Yes it’s a multi level addition, in the same way underground and overground belts merge in an intersection now as they are not actually on a different level, it is just a sprite difference right now that lets objects pass through it.
I think underground service roads would be the easiest and best solution without going multilevel. I have a Terminal designed like an upside down “T” and my carts and trucks must go all the way around. Even when I build Vehicle Depots on the other side it only slightly helps.
Underground Service Roads (like baggge) could be a cool (and very helpful) feature without going all out multi-level.