# \[Page update\] Controlling\_U-turn\_penalties
**URL:** https://www.waze.com/discuss/t/page-update-controlling-u-turn-penalties/69572
**Category:** US Wiki Discussion
**Created:** [October 17, 2017, 2:06pm UTC](https://www.waze.com/discuss/t/page-update-controlling-u-turn-penalties/69572 "2017-10-17T14:06:39Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@nzahn1](https://www.waze.com/discuss/u/nzahn1)
#### Post date: [October 17, 2017, 2:06pm UTC](https://www.waze.com/discuss/t/page-update-controlling-u-turn-penalties/69572/1 "2017-10-17T14:06:39Z")
Implementing the [guidance from staff](https://www.waze.com/forum/viewtopic.php?f=129&t=240784), that unidirectional U-turns on divided highways should use JB to prevent prohibited u-turns not micro-doglegs to ‘break’ U-turn prevention mechanisms.
[Allowing median U-turns](https://wazeopedia.waze.com/wiki/USA/Routing_penalties/Controlling_U-turn_penalties#Allowing_median_U-turns) current
[code]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:
- To allow median U-turns in both directions, break condition #2 by making the median segment (B) {{:Routing\_penalties/U-turn\_minimum|greater}} ‘‘or longer’’
- 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.
[[File:U-turn selective Uturn prevention.png|center]][/code][Allowing median U-turns](https://wazeopedia.waze.com/wiki/USA/index.php?title=User:Nzahn1/unidirectional_U-turn) proposed
[code]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:
- To allow median U-turns in both directions, break condition #2 by making the median segment (B) {{:Routing\_penalties/U-turn\_minimum|greater}} ‘‘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. {{As of|2017}}, a rank 5 user or above is required to install a Junction Box.
{{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.}}[/code]
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### Author:  [@herrchin](https://www.waze.com/discuss/u/herrchin)
#### Post date: [October 17, 2017, 4:48pm UTC](https://www.waze.com/discuss/t/page-update-controlling-u-turn-penalties/69572/2 "2017-10-17T16:48:22Z")
Perhaps remove the opening line completely? Instead of providing general guidance to break one of the 3 conditions, the bullets now provide the preferred and explicit way to handle unidirectional and bidirectional situations.
> [@WoP](#):
>
> To allow a double-left or double-right turn through the median segment, break any one of the above conditions. For example:
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### Author:  [@voludu21](https://www.waze.com/discuss/u/voludu21)
#### Post date: [September 18, 2019, 4:37pm UTC](https://www.waze.com/discuss/t/page-update-controlling-u-turn-penalties/69572/3 "2019-09-18T16:37:26Z")
I would like to do two things to this page:
1. remove the warning box under “allowing median u-turns”. I think this section should now be considered up to date
2. Add a section before examples explaining why we avoid a median segment length that would round to 15m (the value of {{Routing\_penalties/U-turn\_minimum|criterion}} would be 15m)
> [@](#):
>
> ====Technical details====
> WME display rounds segment lengths to the nearest meter (meters setting) or nearest .01 foot (imperial setting). Because the routing server uses a value of {{Routing\_penalties/U-turn\_minimum|criterion}} in deciding whether a median segment is short enough to apply the u-turn penalty, and because rounding means a median segment with displayed length of {{Routing\_penalties/U-turn\_minimum|criterion}} could have a true length in the range {{Routing\_penalties/U-turn\_minimum|criterion}} +/- .5m, it is recommended to avoid a median displayed length of {{Routing\_penalties/U-turn\_minimum|exact}}. {{Routing\_penalties/U-turn\_minimum}} or more when the penalty is to be avoided; {{Routing\_penalties/U-turn\_minimum|less}} or less when the penalty is desired.