Routing penalties has some very outdated information on it. I drafted a revision here, with new information on what is penalized, new information on what is prohibited, a lead section that better explains what a penalty is, a background section that gives a more inclusive history on how penalties have been used, improved links and a note about default navigation settings.
Before writing this, I got confirmation from Yigal that:
Penalty is indeed measured in time, not “points”
Hard turn restrictions are prohibited, not penalized
There is a penalty associated with the number and length of segments on a route
The exact values of penalties (and pruning thresholds for that matter) are not to be disclosed
I also got confirmation from the beta team and QA that the default setting for both Android and iOS is to avoid all unpaved roads and difficult turns.
Note that since route stitching is still not used in production routing, I kept information about how transitions from PLR and PR are penalized. Let me know if I missed anything useful about penalties. Hoping to return this page to relevance.
Your draft page says u-turn penalties are applied when segments are <16M. I thought that we had gotten more conservative and changed the wiki page on U-turns to say <14M
i thought the decision point for U-turns was exactly 15m and we used 14m to disallow and 16m to allow in case editors were not using a script to show exact segment length. is that correct?
On bullet 8 of “Segment Properties,” I would propose a rewording to “in order of increasing penalty.” I find the increasing amounts part somewhat vague.
I even wonder if we should say “in order of increasing penalty”. We can measure things like that today but have we received any assurance that those relationships won’t be changed in the future?
I do think editors need to be warned that they shouldn’t think the penalty on a PR is equal to the penalty on a PLR as we’ve seen problems when they make that assumption.
I have wondered the same thing. Ultimately it’s a bad idea to try to mix these transition penalties. And I’m not sure especially that PR will remain less than OR. We can take that statement out.
Definitely a bad idea to mix. We had a gated community in Ga that backed up to a shopping center. All the inbound traffic routed through the shopping center because there was less penalty for the PLR.
Maybe I’m just tired but kind of blanking on what to write for that… “Be careful about mixing road types that have transition penalties”? Could you propose some better text for a section on that? You are welcome to add it to the draft if you like
I was thinking something along the lines of a brief example for how mixing types can cause issues.
Possible:
“Be aware that mixing penalty levels can affect routing. For example, if the near side of a parking lot is accessible via a private road and the far side via a parking lot road, the navigation engine will prefer to route to the far side (the longer route) to avoid the increased exit penalty.”
I just would like for there to be some sort of example of what a potential problem could be. Just saying “could lead to problems” just prompts a question that they then have to go back to their community to get answered.