Two-way Ramps vs. Routing [Split from WME Validator]

[AlanOfTheBerg]

I would like to see "2-way ramp" removed from the error list for US.

[AlanOfTheBerg]

I would like to see "2-way ramp" removed from the error list for US.

Why? Where in the US is a freeway ramp ever two-way? <puzzled look>

https://www.waze.com/editor/?zoom=5&lat ... 79&env=usa

There's no reason for that small area to be packed with two 1-way segments. Added complexity with no added value goes against the stated Waze Goals. Ramp segments like this are all over and will stay that way because there is no good reason not to.

[AlanOfTheBerg]

The rumor was that two-way ramps have caused routing issues.

I don't know the history of the rumor and have no good way to disprove or prove it.

If you find that, please inform me. I'm not aware of ramps causing routing issues on their own.

When the on-ramp is restricted (closed), will Waze route the wrong way for a short distance over the off ramp to reach the highway?

In any situation like that, there is always the possibility that the routing server will incorrectly (and dangerously) select routing against a 1-way segment, through turn restrictions, etc. That's an unfortunate byproduct of the way the "penalty"-based system it uses. Nothing is impossible.

[AlanOfTheBerg]

It may actually effect the user when the endpoint of the route is on one of the two segments that connects the same two junctions.

This is one of the main issues with the "same endpoint" that affects end-users directly. The routing server may start the user on the other segment instead of the one the car icon is sitting on. To my knowledge, this bug has not been fixed in the server/app.

[AlanOfTheBerg]

Notice the lack of the "keep left" instruction onto the freeway.

It's because the angle wasn't steep enough at the time. Now it does do as you'd expect and say "stay left".

[AlanOfTheBerg]

Notice the lack of the "keep left" instruction onto the freeway.

It's because the angle wasn't steep enough at the time. Now it does do as you'd expect and say "stay left".

I don't think any angle would give a stay left instruction if the two segments in the permalink were ramp segments. The road type continuity would make the ramp to the highway the best continuation and suppress the instruction.

It shows a stay left in livemap instructions.

[AndyPoms]

I just saw this thread...

Recently (last few months) there was a problem with two-way sections of ramps not giving the proper instructions - missing keep right/left on splits, missing turn right/left to enter/exit the ramps. All these problems were solved by removing the two-way sections of ramp.

[bobthedog007]

Me, personally, my concern here is that it could very well be one of those things where at one time it was, in fact, a problem. But now it may not be; they may have fixed that issue. My question is: Have there been any recent examples of this being a problem?

I came across this bug in the last few weeks on a route I often take.

There is a road that passes a fast food drive through and a small loop around the building for the actual drive through, causing the same endpoints problem.

I would drive down the road and turn left onto that small loop and then wait. I would try to route to my next destination from there which would require me to turn right from the loop back onto the road back the way I came.

But waze would insist on only turning left off the loop onto the road, sending me far out of my way and doubling back much further down the road instead of just turning right to get onto the road.

It seemed as if waze was determined not to route me across a segment when I was on the other segment that had the same endpoints.

This happened every single time I went there. I then went and edited it by adding a new node on the loop to see what happened.
Since then it has always routed the much saner and shorter route by turning right from the loop back up the road.

So this same endpoint segment problem is still present it seems and adding a third node definitely fixed it in this case.


This is the loop
I would come from the east then turn south into the loop.

[CBenson]

I don't see why a ramp should be split just because its a ramp. For instance, I don't see why the two way portion of a trumpet interchange shouldn't be mapped with a two-way ramp segment. But eventually they all seem to get edited to two one-way segments.

[CBenson]

Question: In cases such as those, wouldn't it just make more sense to make them two-way streets until get to the point where it actually splits into on/off ramps attaching to the freeway? Is there a reason why that stretch of road segment must be type ramp?

Not sure they have to be ramp, but they shouldn't be streets. If not ramp, they should be typed at least as high as the lower of the types that they are connecting so not to interfere with the long route pruning routines. But, ramps usually just look better to me in those examples to me.