Access restriction dashing and unpaved pattern should be removed on very narrow road signatures

[imagico]

Follow-up issue to #3399.

On very narrow roads with casing, that is in particular:

• highway=service and highway=road at z14/z15
• minor service roads at z16

and to a slightly lesser extent:

• highway=tertiary at z12
• highway=residential and highway=unclassified at z13
• highway=service and highway=road at z16
• minor service roads at z17

the access restriction dashing and the unpaved pattern are poorly readable and it would probably be a good idea to drop them in these cases to reduce noise in the map.

See z12, z13, z14, z15, z16, z17.

[sommerluk]

I've taken a look on this, particularly on the unpaved pattern.

* `highway=service` and `highway=road` at z14/z15

* minor service roads at z16

Width is 2.0. I agree this is noisy.

* `highway=residential` and `highway=unclassified` at z13

Width is 2.5. I agree this is noisy, and I think the reason is that often the road network is dense in such situations:

* `highway=tertiary` at z12

Width is 2.5 (same as for residential/unclassified at z13). I think this is less a practical problem than for residential/unclassified at z13, because typically the road network of tertiary roads at z12 is less dense, and even the unpaved tertiary roads are a bit noisy anyway yet. But I'm also fine removing it.

and to a slightly lesser extent:
* highway=service and highway=road at z16
* minor service roads at z17

Width is 3.5 here. Not much, but it does not seem to create much noisy either. I would leave those as-is.