Full continuity - All segments of the Alternate route must have both name and type continuity with the segment immediately before and the segment immediately after the possible detour - the most resource-intensive continuity check. Reportedly, has been implemented from time to time.

If the first segment after the possible detour is the beginning of a freeway or highway then the first segment and, thus, can only be accessed from ramps or segments of a different road type group, then there can be no direct route according to the criteria above.

DwarfLord wrote:This is wonderfully helpful, thanks.

But another quirk would seem to lurk...

Extending the example, let's say a lightly traveled Minor Highway is completely blocked by a washout, but there is relatively little traffic backup. Let's say further that Waze finds two routes to bypass the washout that leave the mH and then return to it. One alternate route is 350 m long, the other is 4 km long, but both depart the mH and return to the mH at the same junctions.

Because the penalty is applied to the length of the detour, not the length of the direct route, the 350-m detour will be slapped with a ~4-min penalty. The 4-km detour will not.

If the speed on the 4-km route is 45 mph -- 1.2 km per minute -- then the 4-km detour will take 3.3 minutes, which would not be enough to overcome the penalty on the shorter route.

Waze will therefore offer the 4-km detour but not the 350-m detour, unnecessarily adding about 3 minutes to the bypass route. Right?

[EDIT: I originally concluded by admitting this to be a contrived example. However on reflection, we had something similar in the Santa Cruz Mountains last winter. The principle highway linking Santa Cruz and San Jose was covered with a mudslide several times; in one event the slide was considered too unstable to clear safely and the road was closed for days. Waze tried desperately to route people around the slide. Nearly all such bypass routes would have been subject to the detour-length penalty issue. For a indication of what washouts in our mountains can look like, see .]

dBsooner wrote:Changes have been made to the draft Voludu2 has been working on. It is hosted on their user page here: https://wazeopedia.waze.com/wiki/USA/Us ... Mechanisms.

The primary changes:

• Overall:
  • Changed the definition of "BDP" to be consistent throughout as "big detour prevention" and used "big detour prevention (BDP) penalty" where applicable.
• Criteria:
  • Updated to reflect the latest changes, based on testing conducted by Kartografer, with input from PesachZ
  • Wording has been clarified and a flowchart added - please comment on how understandable the latest version is.
  • Added the term bracketing segments to define the segments immediately before and immediately after a detour. This term is used in the criteria section as well as the flowchart. Note: this term is confined to BDP only and is not intended for overall glossary inclusion.

Primarily all changes are within the Criteria section. This is the section we are looking for feedback on. The "Notes" section and SDP (small detour prevention) have not been updated at this time and do not need feedback.

PesachZ wrote: If the direct route is blocked, restricted or marked with an RTC then it will not be considered a direct route since it will not directly connect both sides when the routing iterates through it. This will therefore cancel BDP entirely for this section. This is newish and went I to effect after the issue you quote due to several reports of bad implementation. It is not yet documented since we don't have all the parameters yet.

PesachZ wrote:Discord, Waze USA, #routing, 09/28/2017
3.1 means that there are two completely distinct ways of getting from the before segment to the after segment. 3.2 means that the first segment after the divergent paths merge must be accessible from another segment of the Sam road type group. This other segment can be part of the direct path, or part of a different path or even a stub. Essentially it is checking that the first merged segment is not the terminus of a fwy. @voludu2 (5) CM(edited)
...
just to be clear rule 3 (3.1 & 3.2) are referring to the direct path (which is an alternate path to the possible detour) and not to to the possible detour itself
...
However I'm pretty certain there's been a change made since this was written which i don't have the hard facts on 100% which revokes The BDP mechanism does not determine that there is actually a direct route with name and type continuity, but rather only uses the above two criteria.. i believe we now need a 3.1.1 this direct path must not be itself a detour (it must match name and road type group for all segments with the segments before and after the possible detour).

Discord, Waze USA, #routing, 09/28/2017
voludu2 (5) CM - 09/29/2017 @PesachZ (6) Thanks for the clarification. I would like to work on rewriting 3.1 to make clear that it specifies another path that has no segments in common with the possible detour under consideration, as well as the change to the update. I'll post something on the forum. After that, I will return to clarifying 3.2 to make clear that it can be satisfied by a segment that is not part of the "direct path" being tested in 3.1
PesachZ (6) - 09/29/2017 One caveat although that used to be true for 3.2, with the update to 3.1 requiring a type match for the direct path, it by default will satisfy 3.2 with the direct path as well. @voludu2 (5) CM