Demote Trunk Roads to non-motorway type

[MoKob]

OSM lists trunk as the second-most important road in a country, not necessarily a divided highway.

Right now, the car profile and OSRM in general assume trunk to be just like a motorway. Trunk roads are mapped within many cities, which is why the guidance handlers currently work around normal intersections by checking connections to normal roads.

This is in conflict with some motorways starting directly connected to the road network. To allow assigning correct turns to motorways starting within a city, we should reconsider the treatment of trunks as motorways. This aligns well with what I see in the tests, where many tests use off/on ramps on situations that just really do not look like they should be considered as such.

This would imply

• changing the car profile in terms of the default motorway-like tags
• updating the intersection handlers to reconsider ramp assignments
• assign ramps even when directly entering a motorway

Resolving this issue would turn the above pictured slight left into ramp slight left.

[MoKob]

The main problem here is that trunk roads are different on a by country basis. In Germany we need trunks to be treated like ramps, in US cities, trunk roads are most often not even closely related to ramps. If we want to treat both ways, we would require country awareness #4167

[MoKob]

A case where this triggers in SF: http://map.project-osrm.org/?z=18&center=37.800890%2C-122.424393&loc=37.801082%2C-122.425954&loc=37.800561%2C-122.424479&hl=en&alt=0