[Routing] Ferry routing

[Philip Barnes]

This thread has prompted me to start looking at ferry routing around the
UK. 

I have been using OSRM and have been finding that a big problem is gates
and barriers rather than the actual ferry itself.

An example is in Dublin, the Hollyhead ferry will route you into the
port. But as there is a gate tagged where you leave, routing stops. 

Example 1
http://map.project-osrm.org/10J

Routing is fine, as destination is inside the port.

Example 2
http://map.project-osrm.org/10K

Routing is via Rosslare.

Example 3
http://map.project-osrm.org/10L

Its that gate!!!! I cannot generate a link if I place the start on the
one-way. But the route generated is via Hollyhead/Fishguard/Rosslare. 

Do I delete the gate, or is there a way to tag it so that it doesn't
break routing? I know it is there from a micromapping point of view, but
it will be open when a ferry unloads.

Phil (trig222)