Some of these edits are unfinished - please make sure all edits have correct tags and geometry when finishing.

Please, if you are splitting ways at a tiger tail diverge/merge, update the tags as appropriate.

If that's the case then why did JOSM update to highlight missing markings tags as a warning? For the latter, that's also not impossible, but certainly uncommon

Perfect, nice.

Not strictly required but very good practice and informs of exactly what type of speed limit is in place. A breakdown of the different values is here: osm.wiki/Key:maxspeed:type#United_Kingdom

Hi, please remember to add maxspeed:type tags when adding maxspeed tags. Thanks!

Hey, please remember to add maxspeed:type tags when changing/adding maxspeed tags. Thanks!

Hey, make sure to use the highway_authority_ref tag for road numbers, not the name tag.

Again, I wouldn't be surprised if all those brackets are botches, unless Swansea Road from the A470 to Baverstock Junction is made an A or B-road, which I highly doubt.

So would you like to change osm.org/way/1283395949 and other associated ways to trunk_link now then?

Trust me, as an expert in traffic signs, and having designed a few myself in the past, you can't trust those alone as a source. Fine leave it for now, but no doubt it will be changed back upon roadworks completing.

Knowing sign designers, it seems many don't understand how brackets work. Signs alone isn't a valid source.

If you want to be pedantic, then yes, but for ease of routing during the roadworks I have switched it to secondary now (the more likely route for this road, I doubt it will go to Swansea Road). Being pedantic means also changing the ramps on this interchange and others to trunk_link now, but for ease of routing trunk is used along with the road name.

I believe having raised this there is now a warning message for such values.

Technically yes, but for simplicity the standard is as per the link. It's also perfectly feasible to map a crossing like this I believe osm.org/way/1029898994.
If you want to raise anything in the discussion go ahead, just thought I'd mention it.

Have you seen this discussion on this topic? https://community.openstreetmap.org/t/where-does-a-motorway-begin-and-end/117844

Are you sure the A38 between Carminow Cross and Callywith Junction is primary (highway=trunk)?

Hi, please remember to change maxspeed:type tags when changing maxspeed tags

Hi, please remember to change maxspeed:type tags when changing maxspeed tags

Also, do the turning restrictions at the southern end of the road actually exist?