Poor routing especially at short segments

[fzs122]

This is my first forum post so please be gentle with me. : )

Something I see time and time again is routing problems at short road segments.

This happens primarily at transitions between ramps and surface streets and at intersections between two roads that have been split into their directional counterparts (a pet peeve of mine when it's done outside of the wiki recommendations, but that's something for another time).

I have attached an example of an incorrect route from a problem report. What I suspect is happening is the short segment is being penalized for taking longer than the combination of alternative road segments. Perhaps because the gps is wrong enough to make waze think that someone waiting at the light is stuck on the short segment (over-inflating the travel time for that segment).

bd_rte.png (131.06 KiB) Viewed 403 times

Apart from there being a legitimate temporary blockage at the short segment to cause this otherwise unnecessary route suggestion, what can be done to minimize or eliminate the situation?

Directional arrows currently allow (and previously allowed) the direction and connecting segments have been locked for quite some time, presumably preventing any intermediate tampering.

Please disregard the unnamed segment in the example at the same area of the problem intersection; using that style at an on/off ramp intersection is another question I have, but I don't want to confuse that with the question at hand.

Here is the corresponding permalink:
https://www.waze.com/editor/?zoom=6&lon ... TTTTTTTTFT

Thanks.

[WeeeZer14]

I see this all the time also. Basically Waze hates short segments. Well really the crappy GPS chips in most phones means that Waze has a hard time bein sure that anyone really travels over the short segments.

I don't have a trigger size to say, but in general just try to avoid short segments.

For divided roads that often means either NOT mapping it as a split road or it means using bowties at each and every intersection.


Sent from my iPhone using Tapatalk

[fzs122]

Hi WeeeZer14,
First of all, thanks so much for taking the time to respond to my question.

I am relieved that you mention using bowties as an option for solving this since it is something that I've already attempted with some success.

Recent bowtie-style updates to an overpass near my office weren't received very well by "end-users" (even though it was invisible to the turn/voice instructions, I guess it was enough for people to notice the horizon panning back and forth when they went through the intersection to mark it as a map "problem" rather than recognize it at a map "solution").

I was going to dig up an example of where I've used bowties with success and to my horror I found something that defies the short segment theory we both believe in (I promise this wasn't meant to be a trick question):

01.png (90.53 KiB) Viewed 367 times

https://www.waze.com/editor/?zoom=5&lon ... TTTTTTTTFT

Unless my eyes deceive me, it looks like waze preferred sending a wazer through 3 segments instead of directly left at the node.

Here's a clean image of just the intersection showing the arrows at the node without the GPS Trace or Waze Route overlay:

02.png (62.97 KiB) Viewed 367 times

As an aside, I tried to keep the angle as obtuse as possible to avoid the routing instructions to consider it a turn for wazers that didn't need to turn at the intersection. I know that I've had sharper angles than this without that problem, so I'm not sure where that came from in this case, either.

My resolution for the intersection by the office was to get rid of the dual lanes altogether for a distance far enough away from the ramps that hopefully it will always be cheaper to be routed correctly. However, this approach has also backfired on me when a mapper goes behind me and just adds all the lanes and short segments back again.

[WeeeZer14]

A few quick notes:

1.) In your bow tie example, is a U-turn really allowed? Just be sure.

2.) All the creation and deletion of segments to split and un-split the road is itself going to create tons of issues. Each time something is deleted you are throwing away all the historical data of average speeds and Waze has to start from scratch.

3.) We all have seen some strange routing lately where Waze seems to be avoiding certain left turns by passing the intersection and making a U-turn. So it may not be anything specific to your location. Does that left turn from the Primary Street to the Ramp have a long light by any chance?

[fzs122]

1.) In your bow tie example, is a U-turn really allowed? Just be sure.

Good advice to always verify that. Thankfully, west to east U-turns are allowed at that intersection.

2.) All the creation and deletion of segments to split and un-split the road is itself going to create tons of issues. Each time something is deleted you are throwing away all the historical data of average speeds and Waze has to start from scratch.

Agreed. I'm starting to lock a lot more of the segments involved in un-splits and (unnecessary) splits just begging to happen. That's part of the reason for my original question, because I started to feel like I was being a bit of a mapping snob to lock them, especially if there was some simple resolution to the short segment dilemma that I just wasn't familiar with.

Does that left turn from the Primary Street to the Ramp have a long light by any chance?

My main experience at that intersection is waiting on the exit ramp to either turn left or merge right onto the primary street. It *feels* like the primary street gets preferential light timing, but you may well be correct about those turning left onto the entrance ramp getting even more of a delay. Do you know if the timing of turns is also stored in intersection nodes? I've not considered that until now.

[WeeeZer14]

Do you know if the timing of turns is also stored in intersection nodes? I've not considered that until now.

Waze staff has told us in the past that timing for paths through a junction are stored as well. So if Waze knows it will take 2 minutes to wait for the left turn light, but Waze figures it will take 30 seconds to go to the next corner and make a U-turn then a right, guess which Waze thinks is better