Quite frankly the road layout here is horrible but I did not have the energy to change it. You shouldn't map roads as two oneway ways if the lanes are separated by paint.

A road can either be adopted, unadopted, or private. That's it.

Take my local council. Their website states: "The majority of the roads in Southampton are public highways maintainable at the public expense. These roads are cleaned, lit and repaired by Southampton City Council and are referred to as adopted roads. The remaining roads are private streets [unadopted roads] or private roads. Maintenance of these roads is the responsibility of the adjacent landowners whose property fronts onto the private streets or private roads. The public has the right to use private streets even though they are not maintained by the council."

Quite clear why this road isn't in Norfolk's list of streets. Clearly states "The List of Streets only indicates highways that are maintainable at public expense and does not include streets that are privately maintained" - so unadopted roads aren't included.

That applies to dual carriageways.
Signs are designed for convenience and simplicity, and they can never be used reliably as sources as many have errors or may be outdated (I have a lot of experience with sign design)

Sorry, should have been clearer, not public right of way as in footpath, bridleway etc. but a route the public can use. That's the difference between an unadopted road and a private road - an unadopted road is a public highway that is maintained privately. There should be no restrictions on access.

A road can't be primary one side of a traffic island and non-primary the other side. I don't need to be local to Norwich to know that.

Whatever a sign says that residents or the developers have put up is irrelevant. An unadopted road is a public right of way. No access tags should be used. This does not warrant a discussion for changing.

Topic created https://community.openstreetmap.org/t/uk-speed-limit-on-private-roads/121579/7

So you want to mark all roads as "maxspeed=none" even if there are other speed limit signs, as they're non-enforcable?

maxspeed=none implies there is legally no speed limit (Germany, Isle of Man). I am not convinced it should be used in this circumstance. The legal status around unadopted roads is very blurred, hence why I am of the opinion that tags should be left out (also the fact they are called unadopted roads in the UK meant I've been using the tag "unadopted=yes", but if you want to set a new standard for that, go ahead as there is no official tag).

There is no legal way to define the speed limit, so it's best to leave it untagged and just tag "unadopted=yes". It's what I've done for majority of unadopted roads in southeast.

Fair enough then.

Where exactly is the data for the proposed road tags (speed limit, lanes, etc.)? If it's just from the CGI flythrough, not sure it will be entirely accurate

It looks as though the sign says "no motor vehicles except local buses and loading in signed bays at any time and except taxis and licensed private hire 7am-7pm". Could you confirm this sign is still there if you are a local? If yes, then this road needs additional tags. https://www.mapillary.com/app/?lat=51.748243444054424&lng=-1.2607605644102478&z=17&pKey=801787797187452&focus=photo&x=0.8475438953203797&y=0.4999134951257758&zoom=2.344174976719672

I didn't look inside the ZEZ much, I just intended to edit Speedwell Street but got carried away a bit. I hope the access tags are correct but as I can't see the signs I just did what I could. There seemed to be a lot of superfluous tags already covered by others so slimmed them down. Are you sure 'psv=yes' is correct given taxis are only allowed for part of the time as per 'taxi:conditional=yes @ 07:00-19:00'?

As for the status, as this is restricted to general traffic and only public transport and occasional delivery vehicles are allowed through, this doesn't seem appropriate for a tertiary route - often designating as you say "roads connecting local centres". This doesn't fit that IMO due to the restrictions.

I have updated the speed limits on the A9. There are multiple stretches on the road where signs explicitly state a speed limit of 50mph for HGVs.

Are you sure the old A303 route is now called "Old Sparkford Road" officially, and the new dual carriageway is called "Sparkford Road"?

Please do not do this. The road layout was as it should be already.

Please remember to change maxspeed:type tags when changing maxspeed tags

The tag "maxspeed:type=GB:zone30" is not valid. Please see the wiki page for valid tags: osm.wiki/Key:maxspeed:type#United_Kingdom

It looks like these speed limits might be in km/h. If so, did you convert them to mph, and why?