Right now, they aren't worried about "optimizing" for things such as rail crossings, construction, etc. they are just trying to get it to work well enough that they have: the ability to send out someone with no route knowledge and get off volume in a predictable manner, are able to make a rather accurate prediction as to time on road for a Courier taking out a certain amount of volume.
They want to make the experienced Courier obsolete, that is the goal as of now. In coming years, optimizing the software to account for such items you have listed will obviously be a goal, but now that isn't the overriding concern right now.
It has been awhile since I worked for Express, but with the plot maps that the DRA software generated (from the sampling of actual routes I received that used them a week ago Saturday) I could get back into a truck and get that volume off (in a city which I've never set foot in), and not had any difficulty.
I did do Saturday deliveries as a Courier, and it was hell getting a route which I knew little about and trying to get an optimized stop order before leaving the building, then to actually get in the field and accurately locate those addresses while not spending too much time looking at a map for driving directions to the next stop. With the maps the DRA generates (with all delivery locations plotted out very precisely and numbered), I'd imagine an 8th grader could do the "navigating" (leaving someone a bit older to actually operate the truck).