The route of I-676 around the Ben Franklin Bridge came up in a thread on AARoads today. I had thought it was as shown with only PennDOT having it routed to I-95, but it appears that FHWA agrees with them on their map. They have I-676 going to I-95 in PA; the section in NJ ends at the state line in the middle of the river and the PA side of the Ben Franklin Bridge is marked "S676" as if it was a state route.
<groans> 
Roadgeeks have been debating I-676/Ben Franklin Bridge since the start of internet time. This topic would come around once a year on MTR...20 YEARS AGO. This isn't a dead horse you're beating, it is its grave you're beating. 
Nothing has changed in PennDOT's routing, nor has any new ramps, or roads, been built in over 30 years. Nothing has changed since then.
Markkos' observation is correct, the routing for I-676 was sorted out in the 'Clinched Interstate Mapping' days.
Move along to more pertinent needs, like getting Mississippi's state system to preview, or getting Alabama, California, & Louisiana road systems to active.
Yes, I think there was a thread on the CHM forum that I remember, but at some point, my memory must have completely reversed who logged what. My impression had been that PennDOT logged I-676 to I-95, and that FHWA logged it over the bridge. Then it came up on AARoads, I looked it up, and was surprised to see FHWA log it to I-95. Clearly I was mistaken, but now I feel I accidentally poked a hornets nest...
For some reason, way back to the CHM days, it was the rule that US Interstates are a special case and were mapped by their legal definitions over signage. For example, MD I-595 has been in all along despite being a completely hidden designation.
I've never understood or liked that.
Might be an artifact of Tim's starting off his project as "Clinched Interstate Mapping", and wanting it to be comprehensive (including unsigned routes like I-595 in Maryland, and all of the Alaska and Puerto Rico Interstates). He kept it that way even after the project expanded to non-Interstate routes, for which he got fussbudgety about omitting unsigned routes rather than trying to be comprehensive.
It would not break my heart to remove completely unsigned Interstates, even if that would reduce my Interstate mileage by over 1300 miles (all covered by non-Interstate systems, including the preview Puerto Rico routes system).
But there are situations like I-676 where the signed route differs from that shown in FHWA maps, and it would make sense to stick with the signed route even if technically inaccurate.
Not to mention that the interstate system tends to hold some roadgeek mystique, such that keeping track of stats including the unsigned routes has greater interest than with other systems. But yeah, it all boils down to the fact that, at one time, CHM
only had the interstates (heck, I remember when it was nothing more than the Interstate Highway Browser!).
There probably wouldn't be much loss to removing unsigned interstates in the lower 48.
Nearly all of them are co-signed with something else already in TM, though there are a few that aren't; the Bismarck Expressway and Falmouth Spur could arguably be extended and added to usasf, and the Brooklyn-Battery Tunnel looks similar to the East River bridges, which aren't in the system. The portion of I-296 not in TM as anything else could be argued to be a pair of ramps. Of course, I imagine there are at least a few people who would like to travel on all the given interstates in a given area, even unsigned ones, and this would also leave Alaska and Puerto Rico without Tier 1 systems (in the case of PR, it wouldn't have
any system other than the territorial highways once that is activated, which is unusual for something of its size in the US... and finding its interstates would likely not be easy without TM as a reference). I have to admit, I like having them in, though it does leave little inconsistencies.
