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The Waze [[routing server]] uses a system that penalizes routes to avoid undesirable situations. Penalties are measured in extra time added to the route, on top of the calculated time that driving the route is expected to take based on historical and real-time traffic data. This extra penalty time does not affect the estimated time of arrival, so it is invisible. When multiple routes are compared, however, the penalized route may not be offered even if it is the fastest route, because the invisible extra time makes it look like it takes longer than a non-penalized slower route.
| contact    = http://www.waze.com/forum/viewtopic.php?f=276&t=68126&start=20#p725964
 
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These penalty amounts can be small (seconds) or very large (hours) depending on the condition being penalized. Their values are proprietary and subject to change, so staff have asked that specific numbers not be shared.
| draft      = yes
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The Waze routing servers use a system that associates restricted turns and directions as a penalty amount. When it then compares the different routes, it looks at the cumulative penalty points and the lowest amount of penalty points is the better route.


== Background ==
== Background ==
Waze routing is intended to work in two very different environments at the same time. One uses map information that has been carefully corrected by a group of dedicated editors. The other uses map information that was imported from an external database with no editor corrections. To support both systems the Waze development team decided to use a penalty-based routing system. That means the various segment and junction node properties that restrict certain directions between segments are applied as a routing penalty. For example, a [[Map_Editing_Quick-start_Guide#Turn_restrictions_.28allowed_turns.29|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 incorrectly set as restricted. This provides for some routing in areas that have not been edited carefully or correctly.
Historically, Waze routing was intended to work in two very different environments at the same time. One uses map information that has been carefully corrected by a group of dedicated editors. The other uses map information that was imported from an external database with no editor corrections. To support both systems, the Waze development team decided to use a penalty-based routing system. That means the various segment and junction node properties that restrict certain directions between segments were applied as a routing penalty. For example, a [[Soft and hard turns|soft restricted turn]] indicated by a red turn restriction arrow and a purple question mark does not prohibit the turn, but rather it applies a high penalty to any route through the turn. Since this is the default state of any newly connected road, this penalty permits routing through new roads where no one has driven or edited them to give better data, where no nearby options exist with allowed turns. Hard restricted turns had an even higher penalty in the past, but as the map matured through editing, the Waze team decided to make hard restricted turns an absolute prohibition on routing.
 
Penalties have been used for other segment properties beyond restrictions, and they have also been used for certain road configurations. The list of penalized segment properties has grown with advances in user-configurable navigation settings. Penalized road configurations have been developed to provide a smarter routing experience for the growing user base.


== Segment properties ==
== Segment properties ==
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The following segment properties cause routing penalties:
The following segment properties cause routing penalties:


*[[Map Editing Quick-start Guide#Turn restrictions .28allowed turns.29|Turn restrictions]] and [[Scheduled restrictions#Turns|scheduled turn restrictions]] during the designated time for the designated vehicle type.
*[[Soft and hard turns|Soft restricted turn]] (red arrow with a purple question mark).
*[[Creating and Editing street segments#Set Road Type.2C Direction.2C and Elevation|One-way roads]] against the designated direction of travel and [[Scheduled restrictions#Segments|scheduled segment restrictions]] for the designated time for the designated vehicle type.
*Soft allowed turn (green arrow with a purple question mark, much smaller penalty than soft restricted turns).
*[[Road Types (USA)#Non-drivable|Non-drivable road types]] including Walking Trail, Pedestrian Boardwalk, Stairway, Railroad and Runway/Taxiway.
*[[Partial restrictions#Difficult turn|Difficult turn]] for users with "don't allow difficult turns" or "always avoid difficult intersections" selected in the app.
*[[Best map editing practice#Toll roads|Toll roads]] for clients with avoid toll roads selected in the app.
*[[Creating and editing road segments#Special properties|Unpaved road]] for users with "don't allow unpaved roads" selected in the app, or when segment length exceeds 984.25 ft (300 m) with "avoid long ones" selected.
*[[Road Types (USA)#Dirt|Dirt road/4x4 Trail]] for clients with "don't allow" selected in the app, or when segment length exceeds 300m with "avoid long ones" selected.
*[[Best map editing practice#Toll roads|Toll road]] for all users but much larger for users with "avoid toll roads" selected in the app.
*[[Road Types (USA)#Parking Lot Road|Parking lot roads]] and [[Road Types (USA)#Private Road|private roads]] when transitioning to another road type.
*{{Freeway}} for users with "avoid freeways" selected in the app.
*{{Ferry}} for users with "avoid ferries" selected in the app.
*{{Parking Lot Road}}, {{Private Road}} and {{Off-road}} (with different amounts) when transitioning '''from''' one of these three road types '''to a different road type''' but not when entering these three road types. This is discussed in detail in [[Private Installations]].
*{{Passageway}} for all vehicle types except motorcycle.
<br />
{{Mbox|type=critical|text={{PassagewayUse}}}}
<br />
Note that avoidance of difficult turns and all unpaved roads is turned on by default for users, whereas avoidance of freeways, ferries and tolls is turned off by default.


== Road configurations ==
== Road configurations ==
Other routing penalties are based on road configurations.
Other routing penalties are based on road configurations.


*[[File:MinSegLengthUturn2.png|border|390px|right|Segment too short to allow two left turns]] Waze will penalize a route with two left turns in less than {{:Routing penalties/U-turn minimum}} in [[right-hand traffic]] jurisdictions or with two right turns in less than {{:Routing penalties/U-turn minimum}} in [[left-hand traffic]] jurisdictions.
=== U-turn ===
{{:Editing Routing penalties/Controlling U-turn penalties/Disabled}}<br />[[File:MinSegLengthUturn2.png|border|390px|right|Segment too short to allow two left turns]]The specific details on configuration, and criteria for how this penalty previously operated are documented in the [[Routing penalties/Controlling U-turn penalties|subpage on controlling U-turn penalties]].''
{{clear}}
{{clear}}


*[[File:OffOnFreeway.png|border|390px|right|Ramps should prevent detour]] Waze penalizes some routes that leave a highway or freeway only to immediately return to the same freeway or highway. This is covered in more detail in [[Detour Prevention Mechanisms]].
=== Detour ===
{{clear}}
[[File:OffOnFreeway.png|border|390px|right|Ramps should prevent detour]] Waze penalizes some routes that leave a highway or freeway only to immediately return to the same freeway or highway. It also penalizes routes that use the same node or [[junction box]] twice or are especially "loopy." This is covered in more detail in [[Detour Prevention Mechanisms]].


* When a new node is created along a current or new segment, the node will default to a 5 second penalty through that node until someone drives across it and the [[map tiles]] are rebuilt with the new data. After that point the 5 second penalty is removed and the measured transit time through that node is used.
=== Extra segments and short segments ===
A small penalty is applied to routes with a large number of segments, especially short segments, at least when those segments have recently been created and don't have historical traffic data. The exact amount of this penalty is unclear, as is the effect of traffic data collected through these segments.


== Preventing routes with certainty ==
== Preventing routes with certainty ==
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 alternate routes, such as when Waze finds that the origin or destination is on the penalized segment.
The following conditions prevent routing and do not involve penalties:
* Closure
* Hard turn restriction
* Time-based turn restriction, if conditions are met
* Time-based segment restriction, if conditions are met (except for [[Junction Style Guide#Two-segment loops|two-segment loops]] and routes ending and beginning on the same segment)
* Wrong way direction through a one-way road (except for [[Junction Style Guide#Two-segment loops|two-segment loops]] and routes ending and beginning on the same segment)
* Non-drivable road types: {{Railroad}}, {{Runway}} and the three [[pedestrian path]] types
* Disconnection of one road from another
* Deletion of a road


In the past, many of these conditions created penalties and could not prevent routing with certainty, so disconnection and deletion were necessary. [[Real time closures#Deciding when to use an RTC|This table]] explains the various uses and trade-offs of routing prevention methods.
[[Category:Waze operations]]
[[Category:Waze operations]]

Latest revision as of 06:19, 22 August 2022

The Waze routing server uses a system that penalizes routes to avoid undesirable situations. Penalties are measured in extra time added to the route, on top of the calculated time that driving the route is expected to take based on historical and real-time traffic data. This extra penalty time does not affect the estimated time of arrival, so it is invisible. When multiple routes are compared, however, the penalized route may not be offered even if it is the fastest route, because the invisible extra time makes it look like it takes longer than a non-penalized slower route.

These penalty amounts can be small (seconds) or very large (hours) depending on the condition being penalized. Their values are proprietary and subject to change, so staff have asked that specific numbers not be shared.

Background

Historically, Waze routing was intended to work in two very different environments at the same time. One uses map information that has been carefully corrected by a group of dedicated editors. The other uses map information that was imported from an external database with no editor corrections. To support both systems, the Waze development team decided to use a penalty-based routing system. That means the various segment and junction node properties that restrict certain directions between segments were applied as a routing penalty. For example, a soft restricted turn indicated by a red turn restriction arrow and a purple question mark does not prohibit the turn, but rather it applies a high penalty to any route through the turn. Since this is the default state of any newly connected road, this penalty permits routing through new roads where no one has driven or edited them to give better data, where no nearby options exist with allowed turns. Hard restricted turns had an even higher penalty in the past, but as the map matured through editing, the Waze team decided to make hard restricted turns an absolute prohibition on routing.

Penalties have been used for other segment properties beyond restrictions, and they have also been used for certain road configurations. The list of penalized segment properties has grown with advances in user-configurable navigation settings. Penalized road configurations have been developed to provide a smarter routing experience for the growing user base.

Segment properties

The following segment properties cause routing penalties:

  • Soft restricted turn (red arrow with a purple question mark).
  • Soft allowed turn (green arrow with a purple question mark, much smaller penalty than soft restricted turns).
  • Difficult turn for users with "don't allow difficult turns" or "always avoid difficult intersections" selected in the app.
  • Unpaved road for users with "don't allow unpaved roads" selected in the app, or when segment length exceeds 984.25 ft (300 m) with "avoid long ones" selected.
  • Toll road for all users but much larger for users with "avoid toll roads" selected in the app.
  •  Freeway  for users with "avoid freeways" selected in the app.
  •  • • • • Ferry • • • •   for users with "avoid ferries" selected in the app.
  •  Parking Lot Road ,  Private Road  and  Off-road / Not maintained  (with different amounts) when transitioning from one of these three road types to a different road type but not when entering these three road types. This is discussed in detail in Private Installations.
  •  Passageway  for all vehicle types except motorcycle.


As of October 31, 2018 (2018-10-31), the road type  Passageway  should not be used in the USA. This road type is designed for other parts of the world, where some public roads accommodate only vehicles narrower than cars. At this time, DO NOT use the  Passageway  road type in the USA without explicit champ approval for each instance.


Note that avoidance of difficult turns and all unpaved roads is turned on by default for users, whereas avoidance of freeways, ferries and tolls is turned off by default.

Road configurations

Other routing penalties are based on road configurations.

U-turn

As of December 2021, the Waze routing algorithm penalizing some double-left and double-right turns has been disabled in the United States. The routing server will no longer automatically avoid double-left turns. To prevent u-turns on divided roads, use a Junction box.


Segment too short to allow two left turns
Segment too short to allow two left turns

The specific details on configuration, and criteria for how this penalty previously operated are documented in the subpage on controlling U-turn penalties.

Detour

Ramps should prevent detour
Ramps should prevent detour

Waze penalizes some routes that leave a highway or freeway only to immediately return to the same freeway or highway. It also penalizes routes that use the same node or junction box twice or are especially "loopy." This is covered in more detail in Detour Prevention Mechanisms.

Extra segments and short segments

A small penalty is applied to routes with a large number of segments, especially short segments, at least when those segments have recently been created and don't have historical traffic data. The exact amount of this penalty is unclear, as is the effect of traffic data collected through these segments.

Preventing routes with certainty

The following conditions prevent routing and do not involve penalties:

  • Closure
  • Hard turn restriction
  • Time-based turn restriction, if conditions are met
  • Time-based segment restriction, if conditions are met (except for two-segment loops and routes ending and beginning on the same segment)
  • Wrong way direction through a one-way road (except for two-segment loops and routes ending and beginning on the same segment)
  • Non-drivable road types:  |-|-|-|-|-|-|-|-|-| Railroad |-|-|-|-|-|-|-|-|-| ,  ⁃     ⁃        ⁃        ⁃        ⁃ Runway ⁃        ⁃        ⁃        ⁃        ⁃  and the three pedestrian path types
  • Disconnection of one road from another
  • Deletion of a road

In the past, many of these conditions created penalties and could not prevent routing with certainty, so disconnection and deletion were necessary. This table explains the various uses and trade-offs of routing prevention methods.