This strikes me as a solution in search of a problem...
Way I see it, oftentimes in these situations where a one-way couplet forms a triangle, splitting the difference = cutting straight from one end of the couplet to the other = effectively following one direction. For an example of what I mean, see
ME ME22 I-295 StJohnSt .
As such, I think the way it's currently handled in the HB is the best way to do things, with the one exception that it may be worthwhile to break the 222/272 concurrency between PA501 and US30, as it's possible to drive US222 SB without driving PA272. This would be done by moving the coords of
PA PA272 US30/222 by 0.000001. This would break the Intersecting Routes feature in the HB, but at present that's simply a consequence of "Looks Intentional" NMPs, and something worthy of its own
topic.
For a good head-explody case study in intentional NMPs and breaking false-positive multiplexes, go here, search for US6/MA138@BriSt and click on it in the table, and hit the + key or use the mouse wheel to zoom in.
Or, double-click near the middle (near 41.719440,-71.153808) of the bold-looking blue line south of there, heading toward MA79/MA138@US6_E and keep on pressing + top zoom in. Surprise! It's actually three blue lines, very closely overlaid on top of one another.
(https://github.com/Markkos1992/HighwayData/pull/38)
I didn't look around at the individual commits, as I couldn't tell what file each one was referencing without clicking on it.
Suggest commit messages such as "PA117: Recentering Along US 422", "PA934: Recentering Along US 422", etc.
PA272Lan_N +US30_W http://www.openstreetmap.org/?lat=40.068398&lon=-76.303066 (lines up with US 30 and PA 272, US 30 concurrency would stay as marked now)
The label would actually be PA272_LanN
(PA272Lan_N would imply that there's a "PA272Lan" route in the HB), though I don't recommend adding it.