Detour detection mechanism in the wiki

[CBenson]

What's soon? I've added the page.

[CBenson]

Yes, I think we should. At this point I believe that reliance on the detour prevention mechanism is preferable to using the collector/distributor configurations currently listed in that section of the wiki.

I also think that we now need to state somewhere that when editing interchanges care should be taken to avoid changes in the highway/freeway name and city name through the interchange to preserve the effectiveness of the detour prevention mechanism. The question becomes whether freeway segments should have city names at all, but I don't believe there is a consensus on this issue.

The Europeans seem to be finding significant instances where the detour prevention mechanism does not work as expected. I have been holding off making more significant changes based on some hope that we will get more information from waze regarding exactly how the mechanism works.

[CBenson]

Small Detour Prevention Mechanism

Why the "small" here? To try and differentiate it from "large" detours which are as yet undefined in terms of Waze? I think I'm ok with it, but want a small explanation here. (pun intended)

Very prescient. Waze seems to have now taken to calling this Big Detour Prevention and calling the right/U routing issues small detours.

So how can the title of this section be changed to avoid future confusion.

[CBenson]

Thanks.

Any input on what we should call it at this point?

Highway Off/On Detour Prevention Mechanism?

[CBenson]

Hmm, maybe just say detour prevention mechanism. Then have sections for both "big" detours and "small" detours. Can we say the following at this point?

Waze plans to implement a small detour prevention mechanism to deal with instances where waze calculates that that its a few seconds faster to to continue straight or make a right at an intersection a make a u-turn rather than just turning left. Waze will eliminate such detours if there is under a 30 sec difference in the routes.

[CBenson]

Seems to me that it would be appropriate to note this on the detours page in a "Notes" or "Side-effects" section. I've added this to the detour page, but consider it a draft that can be freely edited. Is there any reason not to put this on the detour page?

[CBenson]

The proposals look good to me.

[CBenson]

In response to the routing discussed here waze has confirmed that the big detour prevention mechanism is merely a high penalty that may not be effective to prevent routing when the traffic on the highway is very slow. I thus propose to change

Waze routing will not present routes over a detour off a highway/freeway and back on that same highway/freeway when all of the following conditions are met:

to read

Waze routing will heavily penalize routes over a detour off a highway/freeway and back on that same highway/freeway when all of the following conditions are met:

We could also add a note that the detour prevention mechanism may not be effective in extremely slow traffic.

[CBenson]

Where is the routing penalty discussion page?

[CBenson]

What should a Routing Penalty section say?

I would suggest something along the lines of:

==Routing Penalties==

Waze routing is intended to work were the Waze map has been carefully corrected by a corp of dedicated editors and where the map is imported without editor correction. For this reason, Waze routing is penalty based. That is, the various segment properties and junction node properties that restrict routes are applied as a routing penalty. For example, a turn restriction indicated by the red turn restriction arrow does not prohibit the turn, rather the turn restriction applies a high penalty to any route through the turn. This penalty based routing system permits routing to a point on street where all turns onto the street are set as restricted. Thus, providing for some routing in areas that have not been edited carefully.

The following segment properties cause routing penalties:

• Turn restrictions (and time based turn restrictions during the designated time for the designated vehicle type)
• One-way roads against the designated direction of travel (and time based segment restrictions for the designated time for the designated vehicle type)
• Non-drivable road types (Walking Trail, Pedestrian Boardwalk, Stairway, Railroad and Runway/Taxiway
• Toll roads for clients with avoid toll roads selected
• Dirt road/4x4 Trail for clients with avoid dirt roads selected
• Parking lot roads and private roads when transitioning to another road type

Other routing penalties are based on road configurations. For example, Waze will penalize a route with two left turns in less than 15 meters in right hand drive jurisdictions or with two right turns in 15 meters in left hand drive jurisdictions. Waze also penalizes some routes that leave a highway or freeway only to immediately return to the same freeway or highway.

If a segment should never be used for routing, it should not be connected to the road network. For example, Waze may route over railroad, walking trail or stairway segments connected to the road network if conditions are such that the penalized route is still found to be the best route. This is common where there are no alternative routes, such as when Waze finds that the origin or destination is on the penalized segment.