[Tagging] Meaning of access=yes on highway=footway?

[Niels Elgaard Larsen]

Greg Troxel:
> 
> Raphael <dafadllyn at gmail.com> writes:
> 
>> I recently got lost with OsmAnd because it wanted to guide me by car
>> along a (public) footpath (highway=footway) tagged with acces=yes.


That happened to me too i 2016. I later wrote about it on this list.
> Is
>> this a routing or a tagging error? That is, does access=yes on
>> highway=footway mean that the footpath is open to all vehicles or that
>> only pedestrians are allowed?
> 
> I think it is both a tagging error and a router error.


No it is just a tagging error. highway=footway implies foot=designated and in most 
countries, motor_vehicles=no, etc.

But if you override that with e.g., access=yes then, well, you have overridden it and 
routers should respect that.

> It's a tagging error because surely vehicles are not permitted on
> highway=footway.

Not necessarily. For example in Denmark there are some footways and cycleways that 
are emergency=yes because the have been carefully designed to allow ambulances and 
police cars to e.g. pass under motorways at strategic points (The police like to have 
some shortcuts available)

> Generally, I would say that access=yes is very often, maybe almost
> always, wrong as a tag.

I agree.

> But, it is also a routing error because highway=footway defines a way on
> which a human could walk (phsyically, setting aside access rules).
> Typically, they are too narrow for a passenger car.  A router should not
> try to use them, even if access is ok, unless there is some width tag of
>> = 2m (2.5m the US - taking the GB view :-).

You are asking too much of routers. And then what about motorcycles, mopeds, horse 
riding, snow scooters, etc?

The widest cycleway in Copenhagen is 10m wide (Dybbelsbro). You could easy drive a 
car on it.

If you tag a footway with access=yes and it is not tagged with a narrow width, then 
why should a router not respect the tagging?

It is not the job of routers to fix tagging mistakes. We have many tools for finding 
bad tagging, and when we find bad tagging, we should just fix it in OSM.

> Basically I'm saying that a router should only use a way if both are
> true:
>    - the way is physically suitable
>    - the permissions are ok


This would also permit motorcycles on footways and pedestrians on motorways tagged 
with access=yes.

> (Also highway=path should not be presumed to be passable by vehicles;
> often it is too uneven or too rocky.)

And it not presumed to be passable by vehicles. Unless tagged otherwise. Which it 
sometimes is.


There are many
highway=path,motor_vehicle=yes,smoothness=horrible
and
highway=path,motor_vehicle=forestry,smoothness=horrible

I have been going on some very uneven paths in Australia in a Land Rover. We assumed 
it was legal.




-- 
Niels Elgaard Larsen