`highway=` classification is determined between junctions. So it can't directly change to another class in the middle.
And again, what is a "main line" can be argued. I can say Shun Long Rd is a very large interchange. Or you can see how long is Yuen Shin Rd, or Tsing Sha Hwy on Tsing Yi. Ma On Shan Rd and Tsing Yi North Coastal Rd may be claimed as entrance / exits as well.
Therefore to avoid such debate, `=motorway_link` is exceptionally used to indicate special problems.

1. This is already the case with Tunnel Area. They are not Expressway, but are using `=motorway`. I have suggested to change them to `=trunk` + `motorroad=yes`. For the issue at hand, `=motorway` is a special class that's not defined by function alone. However, it still needs to follow the convention of classification between junctions. It should not suddenly change in the middle, simply because of the Expressway Area limit
2. Airport Rd only leads to North Lantau Hwy. That's why `=motorway_link` was used as a stop-gap. To indicate it is connected to a `=motorway` only.
3. Tung Wing Rd is a Tunnel Area. Discovery Bay Tunnel is more exceptional, because it is a single carriageway, with no physically raised separation. It also depends on the definition of `_link`=*. Eg some people find Penny Bay's Highway is only an entrance/exit now, so it has been `=motorway_link`.

That's why `=motorway_link` has been used as a stop-gap despite its issues. That was a tentative solution for many problems.
Other debates:
Ma On Shan Road
Tsing Yi North Coastal Road
Tsing Tin Road
Hung Tin Road

`=motorway_link` is to be used where it leads to `=motorway`

Otherwise by this logic, `=motorway_link` has to be changed mid-way. This has been raised and opposed explicitly in some public discussions.

I already indicated this by `motorway=no`. In OSM, `=motorway` and `=motorway_link` are used between junctions, not the exact location.

3. Tung Wing Road is Tunnel Area. Therefore under existing guidelines, it is `=motorway`. However, this was not followed in Discovery Bay Tunnel.

1. In this case, it is because the sections of Airport Rd concerned is only connected to Expressway due to partial interchanges.

Hi please see previous discussions on the subject.
1. This is not in Expressway Area. Together with Tunnel Area, the usage of `=motorway`, `=trunk`, and `=primary` is debated. As a stop-gap, `=motorway_link` has been applied to them.
2. Route 8 ends east of the bridge. It doesn't include the sea channel crossing.

No, they aren't non-existent. Default speeds should still be confirmed.

Please don't upload labels for yourself. This is a public database. Not only is it a worse duplicate, `tourism=apartment` is rented for vacation.

I would disagree. `=service` in Control Area won't be different either.

There had been a discussion about addressing on islands off Lantau caused by Peng Chau being affected by Discovery Bay. Similarly Chek Lap Kok is affected by Tung Chung. If anything, Lamma should be the `=town`. I have set `=suburb` as `=island` is not recognized in addressing.

Please don't add descriptor labels in `name=`. `name=` is for proper names only. Use `description=`.

Please don't interpret "lighthouse" literally. This is a `man_made=beacon` and `seamark:type=light_minor`, not a `man_made=lighthouse` and `seamark:type=light_major`. Don't Tag For Renderer.

Please don't reuse areas while leaving empty blanks elsewhere. There are fillers here.

Descriptive upload comments please osm.wiki/Good_changeset_comments

(sorry for the wide changeset)

(Sorry for the wide changset)

(Sorry for the wide changeset)

What? This is already set as `toll=no`.