Difference between revisions of "Routing penalties/Controlling U-turn penalties"

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=== {{@|Median U-turn penalty}} ===
 
 
{{anchor|Avoiding U turns|Avoiding U turns in box and partial box intersections}}
 
{{anchor|Avoiding U turns|Avoiding U turns in box and partial box intersections}}
{{Mbox|type=forum|text=For the latest discussion on this section please visit [http://www.waze.com/forum/viewtopic.php?t=108731 the wiki forum thread].}}
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{{hatnote|This article discusses double-turn U-turns. For standard one or two segment U-turns, adjust the [[Interface_guide#Junction_Arrows|junction arrows]].}}
[[File:U-turn_Roads.png||360px|right]]
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{{ForumLink|forum=http://www.waze.com/forum/viewtopic.php?t=108731|<nowiki>[Page Update] Intersections / U-turns under 15m</nowiki>|section=yes}}
The Waze routing algorithm sets a [[Routing penalties#Road_configurations|penalty]] for some double-left or double-right turns. This can prevent U-turns at H-style intersections on divided and parallel roads.
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{| style="float: right; width: 360px; border: 0px;text-align: center; line-height: 1; font-size: small;"
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| [[File:U-turn_Roads.png|360px]]
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|-
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| style="padding-bottom: 20px; padding-left:10px;" |''Note:'' The road types displayed in the images might not match the standards for where you edit. Please check your local wiki and with local experts to learn the correct road type to use for '''median segments''' in your area.
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|}
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The Waze routing algorithm has a method of [[Routing penalties#Road_configurations|penalizing]] some double-left and double-right turns. This can prevent U-turns at H or # style intersections on divided and parallel roads.
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It is useful for preventing the sequence of two turns that would make up the U-turn, while still allowing the individual turns. However, if either of the two turns making up the U-turn is illegal or impossible, disallow that turn instead. The U-turn will then not be routed, and the following penalty does not matter.
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==== {{@|Preventing median U-turns}} ====
 
==== {{@|Preventing median U-turns}} ====
A large U-turn penalty is set for a double-left or double-right turn when '''''all three''''' of the conditions below are met:  
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An extremely large U-turn penalty is set for a double-left or double-right turn when '''''all three''''' of the conditions below are met:  
  
 
# '''Three segments''': The U-turn is a reversal of driving direction through three segments: <br>an incoming segment&nbsp;(A), a single median segment&nbsp;(B) and an outgoing segment&nbsp;(C).
 
# '''Three segments''': The U-turn is a reversal of driving direction through three segments: <br>an incoming segment&nbsp;(A), a single median segment&nbsp;(B) and an outgoing segment&nbsp;(C).
# '''Short median''': The median segment&nbsp;(B) is shorter than 15 meters (49.21 feet).
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# '''Short median''': The median segment&nbsp;(B) is equal to {{:Routing_penalties/U-turn_minimum|less}} or less.
# '''In/out parallelism''': The in and out segments (A&nbsp;and&nbsp;C) are  [[#Checking for parallel segments|within ±5° of parallel]] to each other
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# '''In/out parallelism''': The in and out segments (A&nbsp;and&nbsp;C) are  [[#Checking for parallel incoming and outgoing segments|within ±5° of parallel]] to each other.
<br>{{Mbox|type=important|text=It is possible for this method to fail to prevent a U-turn when it is the first segment of a route or reroute. If you observe this method to fail when it is implemented properly, please report it in [http://www.waze.com/forum/viewtopic.php?p=994385#p994385 this forum thread]}}
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<br>
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{{Mbox|type=important|text=It is possible for this method to fail to prevent a U-turn when it is the first segment of a route, or it immediately follows a reroute. If you observe this method to fail in other situations when it is implemented properly, please report it in [http://www.waze.com/forum/viewtopic.php?p=994385#p994385 this forum thread]}}
 
<br>
 
<br>
  
 
==== {{@|Allowing median U-turns}} ====
 
==== {{@|Allowing median U-turns}} ====
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To allow median U-turns in both directions, break condition #2 by making the median segment&nbsp;(B) {{:Routing_penalties/U-turn_minimum|greater}} ''or longer''
  
To allow a double-left or double-right turn through the median segment, break any one of the [[#Preventing median U-turns|above conditions]]. For example:
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To allow a U-turn from only one direction, first setup the intersection to allow U-turns in both directions. Then, add a [[Junction Box]], and restrict the prohibited U-turn route.  A rank {{Rank|jb}} user or above is required to install a Junction Box.  
 
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{{mbox|text=Previously, unidirectional U-turn prohibition on a divided road was set up by breaking condition #3 of the U-turn prevention mechanism through the use of a [[Glossary#mDL|micro-dogleg]].  {{As of|2017}}, Waze staff has expressed a preference that map editors use Junction Boxes in these situations.}}
* To allow median U-turns in both directions, break condition #2 by making the median segment&nbsp;(B) 16 meters (52.5 feet) or ''longer''
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<!-- OLD INFORMATION * To allow a U-turn from only one direction, first set up U-turn prevention for both directions. Break condition #3 on the side where U-turns are allowed. Increase or decrease the angles so that the in and out segments (A and C) are [[#Checking for parallel incoming and outgoing segments|not parallel]]. A [[Glossary#mDL|micro-dogleg]] can be used to change the angle without changing the appearance of the segment.
* To allow a U-turn from only one direction, first set up U-turn prevention for both directions. Break condition #3 on the side where U-turns are allowed. Increase or decrease the angles so that the in and out segments (A and C) are [[#Checking for parallel segments|not parallel]]. A [[Glossary#mDL|micro-dogleg]] can be used to change the angle without changing the appearance of segment.
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[[File:U-turn selective Uturn prevention.png|center]]-->
<br>
 
[[File:U-turn selective Uturn prevention.png|center]]
 
 
<br>
 
<br>
  
 
==== {{@|Checking for parallel incoming and outgoing segments}} ====
 
==== {{@|Checking for parallel incoming and outgoing segments}} ====
  
Condition #3 for U-turn prevention requires that the in and out segments (A&nbsp;and&nbsp;C) are within ±5º of parallel to each other. This is checked by using a ''straight'' median segment as the reference and the [[Scripts#WME_Junction_Angle_info|Junction Angle Info]] (JAI) browser extension to measure angles. JAI may be set for absolute or [[How_Waze_determines_turn_/_keep_/_exit_maneuvers|turn angles]]; using either is OK.
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Condition #3 for U-turn prevention requires that the in and out segments (A&nbsp;and&nbsp;C) are within ±5º of parallel to each other. This is checked by using a ''straight'' median segment as the reference and the [[Scripts#WME_Junction_Angle_info|Junction Angle Info]] (JAI) browser extension to measure angles. JAI may be set for absolute or [[Interactive_junction_instruction_algorithm#Turn_angle|turn angles]]; using either is OK.
  
 
===== {{@|Straight median segments}} =====
 
===== {{@|Straight median segments}} =====
If the median segment&nbsp;(B) is straight, add the angle between the in-segment&nbsp;(A) and median&nbsp;(B) and the angle between the median&nbsp;(B) and out-segment&nbsp;(C). The in and out segments (A&nbsp;and&nbsp;C) are considered parallel if the sum of these angles is {{font color|red|between 175º and 185º}},
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If the median segment is straight, sum the two angles making up the U-turn:
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:# The angle between the incoming and median segments (between A and B)
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:# The angle between the median and outgoing segments (between B and C)
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The in and out segments (A&nbsp;and&nbsp;C) are considered parallel if the sum is {{font color|red|between 175º and 185º}}.
 
<br>
 
<br>
[[File:U-turn_Parallel_Check_Straight.png||680px]]
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{| style="border: 0px; text-align: center; line-height: 1; font-size: small;"
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|-
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| [[File:U-turn_Parallel_Check_Straight.png|680px]]
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|-
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| style="padding-bottom: 20px;" | The short 14m median segment in the above examples satisfies condition #2 for U-turn prevention.
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|}
  
 
===== {{@|Curved median segments}} =====
 
===== {{@|Curved median segments}} =====
If the median segment&nbsp;(B) has been shaped with geometry nodes, it is not straight and cannot be used for determining parallelism. Instead, draw a straight segment connected at the same in and out junctions (where in-segment&nbsp;(A) junctions with median&nbsp;(B) and median&nbsp;(B) junctions with out-segment&nbsp;(C)). Check the angles using this straight segment and delete the segment afterwards.  
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If the median segment&nbsp;(B) has been shaped with geometry nodes, it is not straight and cannot be used for determining parallelism. Instead, draw a straight segment connected at the same in and out junctions (where in-segment&nbsp;(A) junctions with the median segment&nbsp;(B) and where the median segment&nbsp;(B) junctions with the out-segment&nbsp;(C)). Check the angles using this new straight segment, and delete the new segment afterwards.  
 
 
''Note: Be sure the junctions are unlocked, otherwise connecting a temporary segment to locked junctions will produce a save error even if it is deleted prior to saving.''
 
 
<br>
 
<br>
 
[[File:U-turn_Parallel_Check_Curved.png||680px]]
 
[[File:U-turn_Parallel_Check_Curved.png||680px]]
 
<br>
 
<br>
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{{mbox|type=protection|text=Be sure the [[Editing_permissions#Locked_junction|junctions are not locked]] above your rank. Otherwise, drawing a new temporary segment connected to locked junctions may produce a save error even if it is deleted prior to saving.
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{{Expand|
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# Disable the [[Map_Editor_Interface_and_Controls#Settings_Tab|WME setting]] "Draw new roads with all turns allowed" before drawing the new segment.
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# Draw the new segment disconnected from any other segment, then drag the end nodes to connect to the junctions.
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|workaround options when any segments connected to either junction node cannot be edited.
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|nt=yes}}}}
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<includeonly>Please see the [[Routing penalties/Controlling U-turn penalties#Additional examples|Controlling U-turn penalties]] article for more advanced details, and additional examples.</includeonly><noinclude>
  
 
==== {{@|Additional examples}} ====
 
==== {{@|Additional examples}} ====
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| [[File:U-turn_example_2mediansegs-bdp.png|243px]]
 
| [[File:U-turn_example_2mediansegs-bdp.png|243px]]
 
| Cutting a median segment into two may have unintended consequences
 
| Cutting a median segment into two may have unintended consequences
| U-turns are legal at this intersection. Even though U-turn prevention will ''not'' triggered here, Waze will rarely route a U-turn at this intersection. When the railroad was junctioned with the median segment, it cut a single median into two. The two-segment discontinuity between divided roads of Major Blvd will trigger a lower penalty mechanism designed to discourage detours off the main road (see [[Detour_Prevention_Mechanisms/USA#Big_Detours|Big Detour Prevention]], BDP).  
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| U-turns are legal at this intersection. Even though U-turn prevention will ''not'' be triggered here, Waze will rarely route a U-turn at this intersection. When the railroad was junctioned with the median segment, it cut a single median into two. The two-segment discontinuity between divided roads of Major Blvd can trigger a lower penalty mechanism designed to discourage detours off the main road (see [[Detour_Prevention_Mechanisms#Big_Detours|Big Detour Prevention]], BDP).  
 
|- style="background-color: #fff;"
 
|- style="background-color: #fff;"
 
| [[File:U-turn_example_2mediansegs-allowed.png|243px]]
 
| [[File:U-turn_example_2mediansegs-allowed.png|243px]]
 
| Cutting a median segment into two may have unintended consequences
 
| Cutting a median segment into two may have unintended consequences
| U-turns are not legal at this intersection, but Waze may route a U-turn here anyway. Cutting the median breaks condition #1, so U-turn prevention will not trigger. Unlike the railroad example, BDP will not trigger here either since the divided east and westbound roads do not have matching primary nor alternate names.
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| U-turns are not legal at this intersection, but Waze may route a U-turn here anyway. Cutting the median breaks condition #1, so U-turn prevention will not trigger. Furthermore, BDP might not trigger here if all of its criteria are not met.
 
|- style="background-color: #fff;"
 
|- style="background-color: #fff;"
 
| [[File:U-turn_example_curvedU.png|243px]]
 
| [[File:U-turn_example_curvedU.png|243px]]
| A median segment longer than 15&nbsp;m (49.21&nbsp;ft) will always allow a U-turn
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| A median segment {{:Routing penalties/U-turn minimum|greater}} or longer will always allow a U-turn
| While condition #3 requires a straight segment for determining parallel in and out segments, condition #2 is the measure of the length of the median segment itself. Be careful when the space between divided roads is small. Ensure the U-turn segment is longer than 15&nbsp;m (49.21&nbsp;ft) by adjusting its geometry. Conversely, a median segment of any shape can trigger a U-turn penalty if it is not long enough.
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| While condition #3 requires a straight segment for determining parallel in and out segments, condition #2 is the measure of the length of the median segment itself. Be careful when the space between the divided road is small. Ensure the U-turn segment is {{:Routing penalties/U-turn minimum|greater}} or longer by adjusting geometry. A median segment of any shape can trigger a U-turn penalty between parallel roads if it is not long enough.
 
|- style="background-color: #fff;"
 
|- style="background-color: #fff;"
 
| [[File:U-turn_example_parkinglot.png|243px]]
 
| [[File:U-turn_example_parkinglot.png|243px]]
| To ensure proper routing between two closely spaced parallel roads, connect the two with a segment 16&nbsp;m (52.5&nbsp;ft) or longer
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| To ensure proper routing between two closely spaced parallel roads, connect the two with a segment {{:Routing penalties/U-turn minimum|greater}} or longer
| U-turn prevention triggers for both double-left and double-right turns over any road type. If the three conditions for median U-turn prevention are met, a large penalty will be applied, irrespective of whether the turn is onto the same road in the opposite direction or onto a completely different road. Both double-left and double-right turns can be penalized, regardless of country, and can occur on one way or two way segments.
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| U-turn prevention triggers for both double-left and double-right turns over any road type. If the three conditions for median U-turn prevention are met, a large penalty will be applied, irrespective of whether the turn is onto the same road in the opposite direction or onto a completely different road. Both double-left and double-right turns can be penalized, regardless of country, and can occur for one way or two way segments.
 
|}
 
|}
 
</div>
 
</div>
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</noinclude>

Latest revision as of 20:55, 17 May 2019

Bring up comments or questions on this section in
Forum topic unread.gif [Page Update] Intersections / U-turns under 15m.
U-turn Roads.png
Note: The road types displayed in the images might not match the standards for where you edit. Please check your local wiki and with local experts to learn the correct road type to use for median segments in your area.

The Waze routing algorithm has a method of penalizing some double-left and double-right turns. This can prevent U-turns at H or # style intersections on divided and parallel roads.

It is useful for preventing the sequence of two turns that would make up the U-turn, while still allowing the individual turns. However, if either of the two turns making up the U-turn is illegal or impossible, disallow that turn instead. The U-turn will then not be routed, and the following penalty does not matter.


Preventing median U-turns link to this section

An extremely large U-turn penalty is set for a double-left or double-right turn when all three of the conditions below are met:

  1. Three segments: The U-turn is a reversal of driving direction through three segments:
    an incoming segment (A), a single median segment (B) and an outgoing segment (C).
  2. Short median: The median segment (B) is equal to 45.93 ft (14 m) or less.
  3. In/out parallelism: The in and out segments (A and C) are within ±5° of parallel to each other.


It is possible for this method to fail to prevent a U-turn when it is the first segment of a route, or it immediately follows a reroute. If you observe this method to fail in other situations when it is implemented properly, please report it in this forum thread


Allowing median U-turns link to this section

This revision of a section is currently undergoing modifications. The information and guidance is currently considered accurate enough to be followed now. Content is being prepared by one or more users. Do not make any changes before you post a message in this forum.

To allow median U-turns in both directions, break condition #2 by making the median segment (B) 52.49 ft (16 m) or longer

To allow a U-turn from only one direction, first setup the intersection to allow U-turns in both directions. Then, add a Junction Box, and restrict the prohibited U-turn route. A rank 4 user or above is required to install a Junction Box.

Previously, unidirectional U-turn prohibition on a divided road was set up by breaking condition #3 of the U-turn prevention mechanism through the use of a micro-dogleg. As of 2017, Waze staff has expressed a preference that map editors use Junction Boxes in these situations.


Checking for parallel incoming and outgoing segments link to this section

Condition #3 for U-turn prevention requires that the in and out segments (A and C) are within ±5º of parallel to each other. This is checked by using a straight median segment as the reference and the Junction Angle Info (JAI) browser extension to measure angles. JAI may be set for absolute or turn angles; using either is OK.

Straight median segments link to this section

If the median segment is straight, sum the two angles making up the U-turn:

  1. The angle between the incoming and median segments (between A and B)
  2. The angle between the median and outgoing segments (between B and C)

The in and out segments (A and C) are considered parallel if the sum is between 175º and 185º.

U-turn Parallel Check Straight.png
The short 14m median segment in the above examples satisfies condition #2 for U-turn prevention.
Curved median segments link to this section

If the median segment (B) has been shaped with geometry nodes, it is not straight and cannot be used for determining parallelism. Instead, draw a straight segment connected at the same in and out junctions (where in-segment (A) junctions with the median segment (B) and where the median segment (B) junctions with the out-segment (C)). Check the angles using this new straight segment, and delete the new segment afterwards.
U-turn Parallel Check Curved.png

Be sure the junctions are not locked above your rank. Otherwise, drawing a new temporary segment connected to locked junctions may produce a save error even if it is deleted prior to saving.

Click Expand for details on workaround options when any segments connected to either junction node cannot be edited.

  1. Disable the WME setting "Draw new roads with all turns allowed" before drawing the new segment.
  2. Draw the new segment disconnected from any other segment, then drag the end nodes to connect to the junctions.


Additional examples link to this section

Example Tip Details
U-turn example 2mediansegs-bdp.png Cutting a median segment into two may have unintended consequences U-turns are legal at this intersection. Even though U-turn prevention will not be triggered here, Waze will rarely route a U-turn at this intersection. When the railroad was junctioned with the median segment, it cut a single median into two. The two-segment discontinuity between divided roads of Major Blvd can trigger a lower penalty mechanism designed to discourage detours off the main road (see Big Detour Prevention, BDP).
U-turn example 2mediansegs-allowed.png Cutting a median segment into two may have unintended consequences U-turns are not legal at this intersection, but Waze may route a U-turn here anyway. Cutting the median breaks condition #1, so U-turn prevention will not trigger. Furthermore, BDP might not trigger here if all of its criteria are not met.
U-turn example curvedU.png A median segment 52.49 ft (16 m) or longer will always allow a U-turn While condition #3 requires a straight segment for determining parallel in and out segments, condition #2 is the measure of the length of the median segment itself. Be careful when the space between the divided road is small. Ensure the U-turn segment is 52.49 ft (16 m) or longer by adjusting geometry. A median segment of any shape can trigger a U-turn penalty between parallel roads if it is not long enough.
U-turn example parkinglot.png To ensure proper routing between two closely spaced parallel roads, connect the two with a segment 52.49 ft (16 m) or longer U-turn prevention triggers for both double-left and double-right turns over any road type. If the three conditions for median U-turn prevention are met, a large penalty will be applied, irrespective of whether the turn is onto the same road in the opposite direction or onto a completely different road. Both double-left and double-right turns can be penalized, regardless of country, and can occur for one way or two way segments.