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''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| | [[File:DDI Example Dupont.png|thumb|845x845px|none]] | ||
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. | ||
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=== Segment Directionality === | === Segment Directionality === | ||
[[File:DDI Example Dupont - traffic flow.png|thumb| | [[File:DDI Example Dupont - traffic flow.png|thumb|848x848px|Flow of traffic within a Diverging Diamond Interchange|none]] | ||
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. See'' [[usa:Best_map_editing_practice#Dividing_and_un-dividing_divided_highways|How to Properly Divide/un-Divide a Road.]]'' | 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. See'' [[usa:Best_map_editing_practice#Dividing_and_un-dividing_divided_highways|How to Properly Divide/un-Divide a Road.]]'' | ||
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There are 4 junctions in a DDI at which the turn restrictions must be checked - 2 Inner Surface Road Junctions where traffic crosses, and 2 Outer Surface Road Junctions where the road divides/joins on each side of the DDI.[[File:DDI Example Dupont - turn restrictions.png|thumb|871x871px|All restricted turns within a DDI (displayed by using Shift+Z).]] | There are 4 junctions in a DDI at which the turn restrictions must be checked - 2 Inner Surface Road Junctions where traffic crosses, and 2 Outer Surface Road Junctions where the road divides/joins on each side of the DDI.[[File:DDI Example Dupont - turn restrictions.png|thumb|871x871px|All restricted turns within a DDI (displayed by using Shift+Z).]] | ||
===== '''Inner | ===== '''Inner nctions''': ===== | ||
[[File:DDI Example Dupont - turn restrictions - | |||
[[File:DDI Example Dupont - turn restrictions - | ===== Outer Surface Road Junctions ===== | ||
[[File:DDI Example Dupont - turn restrictions - outer - 02.png|thumb|548x548px]] | |||
[[File:DDI Example Dupont - turn restrictions - inner - 01.png|thumb|544x544px]] | |||
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. | 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 Junctions''' | ===== '''Outer Surface Road Junctions''' ===== | ||
[[File:DDI Example Dupont - turn restrictions - outer.png|thumb| | [[File:DDI Example Dupont - turn restrictions - outer.png|thumb|541x541px|Inner (above, at left) and Outer (above, at right) Surface Road restricted turns (displayed using Shift+Z).]] | ||
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. | ||
Revision as of 16:39, 17 February 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
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. See How to Properly Divide/un-Divide a Road.
At-Grade Intersections
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 (Inner Surface Road Junctions). A DDI may also have two Outer Surface Road junctions, where the one way segments transition to 2-way roads segments.
Turn Restrictions
Overview
There are 4 junctions in a DDI at which the turn restrictions must be checked - 2 Inner Surface Road Junctions where traffic crosses, and 2 Outer Surface Road Junctions where the road divides/joins on each side of the DDI.
Inner nctions:
Outer Surface Road Junctions
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 Junctions
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.
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.