There's no rush on this, so I'm happy to discuss the rules for inclusion for a bit.
How about this? Include any segments such that both ends are interchanges and there are no ways on or off in between that are intended for the average traveler. So a dirt road driveway is ok, as would be things like emergency accesses or accesses through service areas. I'm not thrilled that this would eliminate things like I-587 in Kingston, which has roundabouts at both ends, but I do want to eliminate situations where there's a single interchange and normal intersections in either direction.