[Talk-us] Freeway exit tagging

[David Mease]

I thing my reservations about this type of tagging is that this may be "tagging for the router". I still view the turn:lanes scheme as a (probably incomplete) way of describing complex intersections. Tagging simple intersections with this scheme just to get a routing engine to display the correct arrow icon is a waste of time. That data is already in OSM in the form of layout of the roads themselves. The router already knows there is a motorway with an exit node and a motorway link exiting at an oblique angle. The proper icon can be derived from this information. I think we would be better off waiting for the routing engines to get smarter than tagging every simple unmarked intersection with turn:lanes.

> On Aug 29, 2016, at 3:33 PM, Paul Johnson <baloo at ursamundi.org> wrote:
> 
>> On Mon, Aug 29, 2016 at 2:05 PM, Jack Burke <burkejf3 at gmail.com> wrote:
>> > This exit has no turn lane. There is no staging lane prior to the exit where tags could be placed, one should not be created just so that there is a place to put tags. 
>> > This freeway should not be split. You said yourself that the exit is not part of the freeway itself, so tags should not be placed on the freeway.
>> 
>> That's not entirely true.  The exit ramp technically begins in the middle of the far-right travel lane.  If you were to imagine the highway as a train track instead, the exit ramp would have to physically connect to the rail in the lane.  The same concept applies here, and although I've never actually asked one, I'll bet a highway engineer would agree.
> 
> While not a licensed engineer or planner, my major was civil engineering and my minor was transportation planning and I'm fairly familiar with the applicable federal standards.  Without going into semantics, that's actually a very apt description.  One of my mentors, Sam Baldock, also tended to take into special consideration on highways he designed that all movements drivers might reasonably try could be accomplished without having to make lane changes more frequently than legally allowed.  Essentially, consider how crossovers are staggered in a railroad yard enforcing distances between track changes.
> 
> I wish Oklahoma did this, I've come across a few places in Tulsa where US and State highways enter on one side of the roadway and exit on the opposite side a very short distance later, meaning there's actually no way to stay on the same route without making at least one illegal lane change (too close to merge, exit or most recent lane change).
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