Car park entrance/exits

There is a massive difference on OpenStreetMap between inaccurate and accurate, but incomplete, data.

Stub ways showing the direction of service roads entering & leaving car parks clearly fall into the latter category. They have useful information, and are not wrong.

I would politely ask the people removing this information to desist: they clearly have a less clear picture of the situation than the original mapper. I'm afraid it's a case of blindly following a false positive from a QA tool. They should also be requested to revert edits which have removed valid information from OSM.

It may help to add other tags, but I would suggest following a couple of fairly widely used conventions by adding a fixme tag:

• Add fixme=continue on the last unattached node of the way.
• Add a fixme=stub for further survey to the way itself.

A much less used convention would be to add a further way connecting entrance & exit purely to illustrate the correct connectivity. This could be tagged artificial_path=yes, which has been used for rivers/streams passing through lakes and reservoirs.

You can use amenity=parking_entrance, but I don't know whether all QA-tools and validators take it into account.

You could resolve this by adding the missing parking area, even if only approximately.

Add an area to indicate the underground car park. It need not be absolutely precise, but you can probably roughly guess the area (e.g. from the various entries). Tag it as "amenity=parking", "parking=underground", "level=-1", and possibly "fixme=resurvey" to indicate the area is only estimated.

SK53's answer still stands: It is incorrect to blindly correct this, but by mapping it like this you avoid any ambiguity, and provide valuable information (namely that there is an underground car park, which for example routers may offer to people looking for parking).

Is there a way to tag car park entrances and exits, if the route of vehicles within the car park is not known?

I agree. IMHO... Just as streets are usually tagged as unidirectional or bidirectional, All entry/exit points to those roads should be as well. This should help navigation to proper point to the amenity to avoid future glitches that could result in vehicular collisions.

eg http://www.openstreetmap.org/way/228323772 is the exit from an underground car park below the visible upper one

This exit only point will become an unidirectional exit only linked underground to this entry/exit bidirectional parking entry/exit point.

If I can't tag them as one-way, is there a way to tag them as entrance/exit roads and the traffic direction to be interpolated from that?

So my question is similar to the original post.