Feature Request: Access restriction on roads

[westnordost]

The information whether a road is accessible to the general public is currently missing from the vector tiles.

It would be convenient if the access restrictions would be conflated somehow, as on OSM, the access schema is quite complex. E.g. relevant for car drivers is not only access but also motor_vehicle.

[pnorman]

It's not too hard to process the access schema server-side to derive access for car/pedestrian/bike. Generally for rendering you want to simplify access levels into yes, some cases, and not the general public. It's not obvious if we should do that or the styles should.

We also want to avoid having three access attributes on every single road - we don't need to know that cars are allowed on a residential road because that's the norm and to include that property on every road would inflate tile size.

[westnordost]

Right, I think a single access value that applies for the expected vehicle type would be fine for the purpose of displaying a restriction on the map. Suggestions:

1. For all roads down to service roads (but except pedestrian roads), only the access, vehicle and motor_vehicle key is considered. This means that if there is an access restriction for trucks only, this information is not included in the layer, which is fine for general purpose base maps, IMO

2. For values...

• designated coalesces to yes

• permissive coalesces to either yes or limited. I think the latter would be better

• customers, destination, agricultural, forestry, delivery, discouraged coalesces to limited

• permit coalesces to limited. I think it is mostly used for residential parking (residential parking permits). So, in that regard a bit similar as destination for roads.

• (bicycle, horse, ... etc) dismount coalesces to no

• military, private coalesce to no

• all other values are ignored

[pnorman]

I'm +1 on bringing this in to 1.1

[joto]

I like the proposal and the simplification, but I am not sure whether it is meant as only addressing the "car" use case. I think we should at least use names that would allow later extensions to other modes of transport or have the "bike" and "pedestrian" use case straight away. "horse" is probably too niche, "hgv" also too specialized, but it should be possible to add these in an extension without any clashed in naming or so.

Can we have a properly made out wording before voting on this?

[dch0ph]

The approach used in Carto was to coalesce access tags based on the "primary user" e.g. vehicle tags for roads, horse for bridleway etc.

This gives a single output with values yes, restricted, no (+ unknown for unrecognised access types).

Deciding which access sub-types are relevant for highway=path and highway=track is still a problem.

[pnorman]

For all kind values coming from a highway tag have

• car_access=yes/limited/no/omitted
• bicycle_access=yes/limited/no/omitted
• foot_access=yes/limited/no/omitted

The keys for the access tags are first turned into one of the values below

Access value	Attribute
yes	yes
designated	yes
permissive	limited
customers	limited
destination	limited
agricultural	limited
forestry	limited
delivery	limited
discouraged	limited
permit	limited
dismount	no
military	no
private	no
no	no

Other values are removed.

The first access attribute from the table above is taken in the order below.

• car: motorcar, motor_vehicle, vehicle, access
• bicycle: bicycle, vehicle, access
• foot: foot, access

The attribute is taken from the table below