Thanks for alerting me to this thread, James.
It is generally NOT proper to connect any "non-drive-able" segment types to the regular traffic grid. However, this appears to be more akin to the characteristics of an HOV lane, so it would best fall under the Waze Wiki
's guidelines for HOV lanes: "these lanes should be added to the map as separate roads, with the road type as Parking Lot Roads." They should also be connected to the traffic grid at the appropriate junctions (with turn restrictions set to "allowed"); since the type is PLR, they will be ignored by the routing server. The connections will prevent the creation of automatic map problems, while still making allowance for those who are unaware (or who don't care
) that they shouldn't run Waze while on public transit.