From Wazeopedia

Routing server

172 bytes added, 5 months ago
removed second-person and added info on client-based routing and navigation settings
When using the Waze application, Waze servers use routing algorithms to determine the best path for a given route at that particular time. The specific details of the routing algorithms used by the Waze server are not publicly disclosed and ; the following is based on observation, speculation, and some information revealed by Waze staff. It is assumed that the Tthe operation of the routing server is considered to be proprietary and a competitive advantage to Waze. It is also assumed that it The information on this page is subject to change, and that any information that has been revealed might may be incomplete or out of date.
== Client based routing ==
Calculating an optimal route is a difficult task. While the client device app has a routing algorithm included, this is not used unless there is no connection to the Waze server. Client-based routing only uses cached map tiles. It does not use real-time traffic data or reports, because this information is not accessible, and it does not provide an estimated ETA.
== Routing requests ==
When you request a user requests a route calculation, the request is sent to the Waze server. That route is then transmitted back to your the client device and displayed.
The requests for routing vary according to the settings you have chosen for the user's account on your the client device. Under Navigation you one can choose:* Whether to allow or avoid [[toll roads]]* Which, if any, [[Carpool, HOV, Transit lanes|toll and HOV ]] passes you choose to use on this drive apply (some segments are permitted only to those who hold the proper pass)* Whether to avoid [[ferries]]* Whether to avoid freeways{{Freeway|Freeways}}
* Whether to allow, never allow, or avoid long unpaved roads
* Whether to avoid / not avoid [[Difficult turn|difficult intersections ]] (turns marked "difficult"through nodes or junction boxes).* Vehicle type** {{Passageway}} has a type - Some segment types (passageway / narrow alley) and segment specific [[Routing penalty|penalty]].** [[Partial restrictions|Segment restrictions ]] allow or prevent travel by certain vehicle types.
== Missing roads and incorrect junction connections ==
Waze tries to find the best route between you and your destination based on your the above navigation settings. Obviously it can only route based on roads that it knows about, so your a given route will not be optimal if a better route does not have all the roads with correct connections and allowed turns in the [[Waze Map Editor]]. Also if [[Segment length|segments are less than {{:Segment length/Minimum}}]] they can cause routing issues.
== Real-time current road speeds ==
The routing server uses real-time road speeds (from recent Waze app users if available) and combines the historical speed of the segment broken down into 10-15 minute chunks. The time to pass through a segment is tracked separately for each route out of a segment. For example if a segment ends with only a left and right turn (no straight let's say), then the routing engine isolates the time through the segment to turn left and the time through the segment to turn right. This detailed speed information is proprietary & and is part of not displayed in the data Waze sells/plans to sell and won't be displayed through the editorMap Editor.
It is known that Waze uses prefers to use real-time reports of current road speeds by preference over historical average road speeds. Waze also uses traffic congestion reports to reroute around slow traffic. <!-- Early versions of the client would also report when traffic speeds were good - this was removed due to map clutter. But Waze will still be receiving this information. -->It is assumed that the speed The speeds of any Wazer ahead of you recent Wazers traveling on a stretch of road will be factored into the speed used when your route is calculatedgiven to subsequent Wazers traveling on the same road.
As the number and density of Wazers grows, this real-time data takes on a greater importance. This emphasis is partly a reflection of Waze's original goal to create optimal commutes. As Waze has grown to be used as a more general -purpose GPS navigation device over roads less traveled, the historical average road speeds becomes more important.
Since Waze uses the future expected time you expect to be at of arrival onto a road segment in order to calculate the expected speed on that segment, it cannot use real -time data when your trip time moves into a too far in the future time slot. So longer trips (on the order of more than 30 minutes (and on average or more than 15 minutes) will include future time slots where current traffic data is not available when initially calculated. When you enter a new time slotAs the trip progresses, any real-time traffic data that is available causes your the client to recalculate your the route and the ETA and reroute you at that point.
== Fastest routing ==