User:TerryPurdue/Junction Style Guide/Interchanges View history

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(→‎Diverging Diamond Interchange (DDI): Images have been replaced and reformatted with Ft Wayne, IN Example at Dupont Rd. Minor copy/formatting changes)
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== Diverging Diamond Interchange (DDI) ==
== Diverging Diamond Interchange (DDI) ==
[[File:JSG-Interchanges-DDI-Overview.png|800px]]


''See also:'' [https://en.wikipedia.org/wiki/Diverging_diamond_interchange Diverging Diamond Interchange] article on Wikipedia.
''See also:'' [https://en.wikipedia.org/wiki/Diverging_diamond_interchange Diverging Diamond Interchange] article on Wikipedia.
 
[[File:DDI Example Dupont.png|thumb|587x587px]]
Diverging diamond interchanges (DDI) are a type of diamond interchange in which the two directions of traffic cross one another on each side of a limited-access roadway. A DDI may pass over or under the limited-access roadway.
Diverging diamond interchanges (DDI) are a type of diamond interchange in which the two directions of traffic cross one another on each side of a limited-access roadway. A DDI may pass over or under the limited-access roadway.


This type of interchange is unusual, in that it requires traffic to briefly drive on the opposite side of the road from what is customary for the jurisdiction. However, the DDI's design controls the drivers line of sight to ensure the cross-over action feels natural and goes unnoticed.
This type of interchange is unusual, in that it requires traffic to briefly drive on the opposite side of the road from what is customary for the jurisdiction. However, the design of the Diverging Diamond Interchange controls the driver's line of sight to ensure the cross-over action feels natural and goes unnoticed.


=== Segment Directionality ===
=== Segment Directionality ===
 
[[File:DDI Example Dupont - traffic flow.png|thumb|585x585px|Flow of traffic within a Diverging Diamond Interchange]]
All ramp and surface street segments are set as one-way.
All ramp and surface street segments are set as one-way. If you are creating a DDI along a road which is not divided, divide the road, first. [link to how to wiki on properly divide the road]


=== At-Grade Intersections ===
=== At-Grade Intersections ===


[[File:JSG-Interchanges-DDI-AtGrade.png|800px]]
The two


==== Junctions ====
==== Junctions ====
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==== Turn Restrictions ====
==== Turn Restrictions ====
 
[[File:DDI Example Dupont - turn restrictions.png|thumb|871x871px|All restricted turns within a DDI (displayed by using Shift+Z).]]
'''Overview'''
'''Overview'''


[[File:JSG-Interchanges-DDI-AllRestrictions.png|800px]]
Disable the TWO turns from one-way segments to the segments carrying traffic the ''opposite'' direction at both inner surface road intersections, for a total of four disabled turns.
 
Exactly '''six''' turns are disabled in all Diverging Diamond Interchanges.


'''Outer Surface Road Intersections''':  
'''Outer Surface Road Intersections''':  
 
[[File:DDI Example Dupont - turn restrictions - outer.png|thumb|583x583px]]
[[File:JSG-Interchanges-DDI-OuterRestriction.png|800px]]


Disable the SINGLE turn from the one-way segment carrying traffic ''exiting'' the DDI to the one-way segment carrying traffic ''entering'' the DDI at both outer surface road intersections, for a total of two disabled turns.
Disable the SINGLE turn from the one-way segment carrying traffic ''exiting'' the DDI to the one-way segment carrying traffic ''entering'' the DDI at both outer surface road intersections, for a total of two disabled turns.


'''Inner Surface Road Intersections''':  
'''Inner Surface Road Intersections''':  
[[File:JSG-Interchanges-DDI-InnerRestriction-01.png|800px]]
[[File:JSG-Interchanges-DDI-InnerRestriction-02.png|800px]]
Disable the TWO turns from one-way segments to the segments carrying traffic the ''opposite'' direction at both inner surface road intersections, for a total of four disabled turns.


=== Elevations ===
=== Elevations ===


Elevations are set relative to the limited-access road passing over or under the DDI, with all segments that connect at at-grade intersections having identical elevation.
Elevations are set relative to the limited-access road passing over or under the DDI, with all segments that connect at at-grade intersections having identical elevation.

Revision as of 16:08, 10 January 2017

Diverging Diamond Interchange (DDI)

See also: Diverging Diamond Interchange article on Wikipedia.

Diverging diamond interchanges (DDI) are a type of diamond interchange in which the two directions of traffic cross one another on each side of a limited-access roadway. A DDI may pass over or under the limited-access roadway.

This type of interchange is unusual, in that it requires traffic to briefly drive on the opposite side of the road from what is customary for the jurisdiction. However, the design of the Diverging Diamond Interchange controls the driver's line of sight to ensure the cross-over action feels natural and goes unnoticed.

Segment Directionality

Flow of traffic within a Diverging Diamond Interchange

All ramp and surface street segments are set as one-way. If you are creating a DDI along a road which is not divided, divide the road, first. [link to how to wiki on properly divide the road]

At-Grade Intersections

The two

Junctions

As with all at-grade intersections in Waze, all DDI at-grade intersections are modeled with junction points, including the two signaled intersections where opposing directions of traffic "cross over" each other.

Turn Restrictions

All restricted turns within a DDI (displayed by using Shift+Z).

Overview

Disable the TWO turns from one-way segments to the segments carrying traffic the opposite direction at both inner surface road intersections, for a total of four disabled turns.

Outer Surface Road Intersections:

Disable the SINGLE turn from the one-way segment carrying traffic exiting the DDI to the one-way segment carrying traffic entering the DDI at both outer surface road intersections, for a total of two disabled turns.

Inner Surface Road Intersections:

Elevations

Elevations are set relative to the limited-access road passing over or under the DDI, with all segments that connect at at-grade intersections having identical elevation.