Now that's just too cool.
One odd thing I note is that unclinched segments are sometimes but not always layered on top of clinched ones. See for example here:
Unclinched 298 is layered under clinched 481 (as, IMO, it should be), but unclinched 290 and 5/92 are layered over it.
I'm not seeing any particular pattern as to what goes over versus under. I even note that in cases where the same two routes cross multiple times, they don't necessarily maintain consistent layer order. My unclinched US 11 in VA is layering over my clinched I-81 in VA at almost all crossings... except the ones at exits 195 and 213. At those two spots US 11 is underneath.
I tried reloading a few times and it appears what goes over versus under remains consistent each time the map renders.