Page 1 of 1

Multi-deck bridges: Combine directions of travel?

Posted: Mon Apr 11, 2011 10:34 pm
by AlanOfTheBerg
I have been looking more and more at urban areas where a separated interstate or other highway "come together" in a bridge over parts of a city or water. This obviously presents some difficulty with mapping properly. In Cartouche, to be accurate to reality would make editing nearly impossible with current functionality because you can't click to the select the lower roadway. So, these appear as slightly offset roads. I'm curious about the effect of GPS tracks on these roads: will they eventually "pull together" and the roads will show as nearly being on top of each other?

So, two things: 1) this made me wish more for the ability to display by Level in Cartouche so we could truly overlap the roads, but then be able to edit in a "layered" fashion by Level.

2) Would it be any easier if this roadway were turned bi-directional for these overlapping stretches? I imagine it might turn out OK, even for routing, because you just split into 1-way road segments when appropriate both for the primary road and ramps.

I kind of want to do a proof of concept to see how it works out, but I don't live close enough to such bridge to make testing easy to do without burning a lot of gas.

What are the thoughts of the community?

Re: Multi-deck bridges: Combine directions of travel?

Posted: Mon Apr 11, 2011 11:43 pm
by AlanOfTheBerg
Thanks for the thoughts so far. After pondering a bit more, I came upon a reason to not change it to a bidrectional road: Exits and allowed turns. Because Waze can ignore the turn restrictions imposed by an editor, I can see the case where routing would have you trying to exit on a road specific to the opposite direction (and on a different level) than is possible. Unless we get the ability to get routing to 100% adhere to explicit turn restrictions, I am not convinced my idea will benefit.

Re: Multi-deck bridges: Combine directions of travel?

Posted: Mon Apr 11, 2011 11:00 pm
by hallmike
I'd probably make them a single two-way road since it shouldn't affect GPS or navigation. Layering two separate roads directly on top of each other will cause problems for editing. Eventually a well-meaning map editor is going to see a one-way road, and change it to two-way not realizing there is another one way directly below. Even if there was a 'levels' layer in Cartouche, you'd almost have to know there was a hidden road there to remember to use it because it would be needed so infrequently.

Re: Multi-deck bridges: Combine directions of travel?

Posted: Mon Apr 11, 2011 11:48 pm
by hallmike
Good point. Adding a separating line would help, but it seems every plan has it's flaws with the current editing system.

Re: Multi-deck bridges: Combine directions of travel?

Posted: Tue Apr 12, 2011 7:38 am
by harling
AlanOfTheBerg wrote:1) this made me wish more for the ability to display by Level in Cartouche so we could truly overlap the roads, but then be able to edit in a "layered" fashion by Level...
See http://waze.uservoice.com/forums/59225- ... oads-layer

Re: Multi-deck bridges: Combine directions of travel?

Posted: Mon Apr 11, 2011 10:46 pm
by OscarC
I would be interested in hearing from support themselves.
I visit San Francisco at least once a year so I have some edit permissions out there and I was trying to figure out what to do with the multitudes of these kinds of freeways through the city and around the bay.

They way it stands now, just keeping them slightly overlapped and making sure they are at the right levels is the only way but gets very confusing. I also don't remember which freeway it was but there is also at least one where there is one bi-directional freeway above another bi-directional freeway. Not sure how it work, but the routing worked fine the whole time I was driving around out there.

I wonder what is the "proper" way to do these? I've tried searching the forums but couldn't find anything.

Re: Multi-deck bridges: Combine directions of travel?

Posted: Tue Apr 12, 2011 9:00 am
by Timbones
I know of one overlapping road in England: Tinsley Viaduct by Sheffield. The Motorway runs over the top of another road, yet in Cartouche the minor road is shown be either side of the Motorway. I'm not sure if this is 'proper' though Google maps also does the same, as does Bing.

If navigating from A to B using either road, the client should keep you stuck to the appropriate road. If not navigating, then you might bounce on to the wrong road perhaps, but maybe that doesn't matter?