Users are generally not faulty, they just trust what the common editors allow them to do without warning them.

Merging ways with distinct tags or not members of the same sets of relations should open a conflict resolution editor allowing to see the differences and accept merging tags, or reject it (notably for distinct relations, these relations need to be merged separately if needed, using the same checks on tags and sets of parent relations)

The same remak applies when splitting ways (here also the parent relations need to be all updated in their lists of members), but most often it is simple to repair if a relation is forgotten.

In JOSM, the set of parent relations is not automatically loaded for all ways when merging or splitting them: but JOSM still does not automatically download the parent relations. You have to do it just before merging/splitting ways, pressing CTRL+ALT+D.

However the data server frequently returns 5xx errors when looking for parents (this error isn't reported by dialog or notification on the screen: you see it only on the console, provided that JOSM is launched from a command line window to see it, or by enabling the console window in the Java config menu. Unfortunately, if you close that window, there's no way to reopen it. Suggest JOSM to add an panel to show what is sent to the std-output.

If the server returns an error, nothing happens in the editor, users may feel that all parents are loaded, when they are not. The work around (if you see this error), is to zoom in on a tiny area around the node of the way to split or connecting ways to merge, and then download all objects in that area: the OSM server does not fail downloading all parents of these ways, when it fails by querying only the lists of parents and loading them: this is still a bug/performance issue on OSM server!

In the ID editor, there's a separate old unsolved issue, which occurs when splitting ways that are members of relations: the newly created way is just added at an inaccurate position at end of the list of members, instead of being inserted immediately before or after (depending on the connection of the other end nodes with other members before or after that way).

This creates havoc in many relations that expect a correct ordering, and complicates a lot the reparations that could be done later when the geometry needs to be repaired (not just for closed rings in multipolygons, but as well for linear objects such as associatedStreets/rivers...).

ID should preserve the continuity of member ways as much as possible, and when splitting ways, it is evident that both parts should NEVER be separated in the list of members.

iD unfortunately makes it way too easy to do this. Potlatch 2 also lets you commit an untagged way without any sort of warning (in fact when I was still switching from iD to Potlatch 2 just to add parallel ways, and then switching back to do the rest of a dualize, I took advantage of this). JOSM will at least warn you, but how many newbie editors use JOSM?

That's not so different from other countries. The highway tag should be used to tag the road classification, not the road's look.

Absolutely Harry. I'm keeping a careful eye on this post because I definitely don't want it to turn into a set of "slag off the noobs" answers. I'm interested in finding where the common problems are so we can help the noobs (and everyone else).

As a new user who's registered but not (yet) edited the map, I'll suggest that some sort of introduction to editing the map is desperately needed. Or if there is one, it needs to be much more prominent; I found my way to this "help centre" looking for such a guide, and still haven't found one. I'll be glad to have a go at mapping once I figure out how!

Update: Via the blog post linked above, I found my way finally to the Beginners' guide, but I'll suggest that it should be much easier to find!

I'm not surprised that MANY people sign up then give up. The instructions and answers are spread over many different systems and I haven't found answers to some pretty basic questions yet. I had to create a second login to post this comment and more logins are required to participate in discussion groups. I tried watching a video, but it's just too large for my rural connection. I am very discouraged at this point. I edited databases from '75 to '88 and continued with systems design work until '01 but I'm not sure that I can find out how to help here.

Hello, I registered today since I am using OSM heavily on my ANDROID phone during my trip in Japan and intend to contribute. Looking for a tutorial, I came here. Here a good tutorial on creating OSM maps: https://help.openstreetmap.org/questions/28251/interactive-tutorial-to-getting-started-editing-osm including the following links: http://learnosm.org/en/ http://wiki.openstreetmap.org/wiki/Beginners%27_guide This should save you at least 30 minutes of searching around for tutorials, beginners guides, OSM basics, etc.....

I would not classify this as mistake, people are not obliged to map. Contributing something that you consider not the most important thing is NOT a mistake.