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Junction Style Guide

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When representing The following article contains key information on properly creating junctions (a.k.a. intersections, cross roads, corners, etc.) between roads, we sometimes have to blur and the lines roadways between the physical and logical worldsthem. The primary goal should be Be sure to represent things as simply as possible and only introduce complexity to deal with an issuereview it in its entirety before editing the map.
== The Basics &larr; START HERE Simple is better == Lets start with the very basic case of one road branching off from another. Most of the time they will probably meet at close to a 90 degree angle. This is the simplest situation to deal with since the physical and logical views of the roads match up very well. : [[Image:Jct_3_90.png]] But you will probably find roads that meet at odd angles as well. Even in urban areas with rigid grids, you will often find at least one road that has existed since prior to the establishment of the grid which cuts through town at strange angles. The initial urge will be to represent the junction as it is in the physical world - two lines running into each other at some angle. : [[Image:Jct_3_45.png]] But there are issues with this method. Depending on the angles, the client may give a "Keep Right" instruction to the driver when a "Turn Right" instruction is more appropriate. In some cases, it is even possible the angle may be such that no instruction is given at all. Or worse yet, the routing engine may determine that it isn't possible to make a very sharp angle and not suggest a turn (in the example image, headed south and then turning left to head east). To eliminate ambiguity, we need to treat the junction from a logical point of view. Since we want to be given basic "Turn Left" and "Turn Right" instructions, we have to treat it like it was a basic 90 degree intersection. But how do we do that when the roads don't actually diverge at 90 degrees? What we need to do is to add some geometry nodes to make the branch road leave the main road at close to 90 degrees, then we gradually curve to match the true departure angle. : [[Image:Jct_3_45_curve.png]] Now we have a junction that logically works like a basic 90 degree junction but it also fits the reality of the physical world. Here is a completed real world example:
: [[Image:Jct_3_45_exWhen representing junctions, intersections, interchanges, cross roads, corners, etc., the Waze map does not need to perfectly match the road layouts it represents. The primary goal is to represent the real world as simply as possible in the maps and only introduce complexity in the maps to address complex issues.png]]
A ramp to == The basics ==This guide requires a highway is another good example where additional geometry nodes are helpful. Especially since most ramps diverge at a very small angle from complete understanding of editing the roadmaps with [[Waze Map Editor]] (WME).
=== Map editing 101 ===Although it is highly recommended to read the [[editing manual]] before touching the map, it is required that you do not continue with this guide until you have read the following: * [[Image:Jct_ramp_no_geo.pngMap Editing Quick-start Guide|Map Editing Quick-start Guide]]* [[Creating and editing road segments#Junctions|Moving and removing junctions]]
=== Junction definition ==={| class="Wikitable floatright"| [[Image:Junction_selected.png|50px|border]]| [[Image:Uneditable_junction.png|50px|border]]| [[Image:junction_unsaved.png|50px|border]]|}The drawback in this case (which also exists for the side road example above!) is that it may be very hard to see and click [[Glossary#Junction or Junction Point|Glossary on Junctions]] provides details on the turn restriction arrows how junctions can appear differently in the editordepending on its state or condition.
A junction is made up of three things: [[Image:Jct_ramp_no_geo_arrow.png]] But if we just add one # Two or more geometry node to make the departure angle at the junction itself closer to 20 or 30 degrees... : road [[Image:Jct_ramp_w_geo.pngCreating and editing road segments|segments]] ...now # One point where all the arrows are visible and accessible. Note that you can also press 's' in segments meet (the editor to '''s'''pread or '''s'''eparate the arrows at a junction if you still have difficulty clicking on an arrow. (see [[Keyboard_shortcut|Editor Keyboard Shortcutsjunction point]] for more tips.itself: # [[Image:Jct_ramp_w_geo_arrow.png]] We can easily scale the above approaches to a fourMap Editing Quick-way junctionstart Guide#Turn restrictions . Again we can expect to mostly see angles close to 90 degrees28allowed turns: [[Image:Jct_4_90.png‎ 29|Turns allowed or restricted]] And if we have when traveling from one segment to another through that odd street cutting across town at an odd angle, we again want to avoid the odd angle at the junction...point : [[Image:Jct_4_45.png]] ...and we want to use geometry nodes to bring the actual junction to 90 degrees. You can zoom in as close as you can and add a single geometry node on each side. This will give us the proper angle but make it virtually invisible to users so it looks just like the physical world. : [[Image:Jct_4_45_curve.png]] The above image is what you would see zoomed in as close as possible. Zoomed back out, it looks just like the image showing the junction without any geometry nodes. And here is a real world example at a zoom level where you can still see the geometry adjustment we added: : [[Image:Jct_4_45_ex.png]]{{clear}}
== Controlling Turn Instructions ==
{| class="Wikitable floatright" cellpadding="5" border="1" style="text-align:center; border: 1px solid darkgray;"
|-
| Keep Right || Keep Left
|-
| Turn Right || Turn Left
|-
| Exit Right || Exit Left
|}
Turn instructions are critical for proper client navigation. They are controlled by:
* The angle set between segments at junctions.
* The road names.
* The road types.
Before going further, make sure you understand Review the mechanics of article [[Map_Editing_Quick-start_Guide#Turn_restrictions_.28allowed_turns.29Junction Style Guide/Controlling turn instructions|controlling turn restrictionsinstructions]] in for a complete understanding of the Map Editor. If turns are not properly enabled requirements and restricted, you will never get the instructions you desireissues surrounding this topic.
In the Basics section above, we touched on how to ensure a "Turn left/right" instruction would be given over a "Keep left/right" instruction.== Surface Streets ==
Details of the mechanics behind this can be found on the === Intersections ==={| class="Wikitable floatright"| [[How_Waze_determines_turn_/_keep_/_exit_maneuversFile:Jct 3 90.png|How Waze determines turn / keep / exit maneuversx100px|border]] page, but here is a quick summary| [[File:Jct 4 90.png|x100px|border]]| [[File:Jct ramp no geo.png|x100px|border]]|-| colspan=== Geometry ==="3"|[[File:4waysplitsplit.png|border|center|169x169px]]|}Basic intersections involve three or four road segments meeting at a single point. Some more complex variations resemble H or # shapes.
Some of the complexity of the back-end algorithms can be avoided if we try to treat junctions with the logical view in mind as was done in the previous examples. If In all junctions you edit follow just a few basic forms, cases it will be much easier is important to predict configure these intersections properly. Detailed information is covered in the behavior of an individual junction[[Junction Style Guide/Intersections|Intersections]] article.{{clear}}
* Approximately '''90''' degree departure angle = '''Turn'''
* Between '''20 and 30''' degree departure angle = '''Keep''' (or Exit for Ramps)
This knowledge allows us to control how a junction behaves by modifying a single geometry node in most cases. This is often useful for [[At-Grade_Connectors|At-Grade Connectors]] where sometimes we prefer a "Keep right/left" and other times a "Turn right/left" would be more appropriate.=== No Outlet Roads ===
If we keep the departure angle Roads which only have one way in and one way out can present challenges to the 20 to 30 degree rangerouting server, we would get a "Keep Right" although they seem simple to follow the curved one-way connector:our minds.
: [[Image:Jct_at_grade_keep.png]]==== Dead Ends ====
But if we move Dead Ends (a.k.a. No Exit, Closed, No Through Road, No Outlet) are road segments that simply end, with no continuation or connections at one geometry node end. In some areas, a Dead End may be synonymous with a [[#Cul-de-sacs|Cul-de-sac]]. In the US, a "No Outlet" sign may be used to create indicate a road which itself is not a 90 degree angledead end, now we would receive but it only connects to other dead end roads. It can also be used as a "Turn Rightfriendlier" instructionalternative to the typical Dead End sign.
: [[Image:Jct_at_grade_turnWithin the Map Editor it is possible to represent a dead end road with multiple segments if there are private driveways or parking lot roads mapped and connected. In that case, only the very last segment is considered the dead end segment.png]]
=== Segment Naming [[File:Jct dead end.png|left|border]]Make sure that there is a junction indicator (the small blue dot, not just a geometry node) at the very end of the segment. While this one segment does not actually constitute a junction, the small blue dot is a visual indicator to the editor that the end of this segment is properly set up. This is necessary to ensure proper routing out of the segment. See the Cul-de-sac section below on when and Type ===how to fix this.
Besides [[File:Jct dead end ex.png|right|border|200px]]This final junction indicator must be located near the geometry end of the road segments, but it should be located where there is still pavement as not to negatively impact client routes. Waze only considers the names and types road fully traversed if both ends of the segment are fully crossed. If the junction indicator at the end of the segment happens to be at the edge of the pavement (or off of the segments come into playroad surface if aerials are not exactly aligned), it will be very difficult for a driver to cross that junction. A good rule of thumb is to have the end of the segment the same distance from the end of the pavement as it is from each side of the road.
A basic rule of thumb With such a placement, the driver is that if you want given a turn chance to be announced, having a different name will improve the chances cross that junction indicator for that will happensegment. For Also check for the Atproper u-Grade Connector example above, the connector should have a different name than the road it is leaving (See turn setting as covered in the [[AtMap Editing Quick-Grade_Connectorsstart Guide#How_to_name_the_connectorU-Turns at the end of dead-end-streets|How to name the connectorbest practices article on u-turns]] section of the At-Grade Connectors page).
== No Outlet Roads == Cul-de-sacs ====
Roads which only have one way in and one way out can present challenges to the routing server although they seem simple to the human mind''See also: [http://en=== Dead Ends ===wikipedia.org/wiki/Cul-de-sac Cul-de-sac article on Wikipedia]''
Make sure that there is A Cul-de-sac (a junction node (not just .k.a geometry node. Court in the US) at the very end of the segment. This is necessary to ensure proper routing out a common treatment of the segmenta dead end street in a residential neighborhood.
: In almost every situation, a cul-de-sac should be treated exactly as a dead end street, with the final junction indicator in the center of the bulb of the cul-de-sac. Be sure the free end of the final road segment has small blue dot displayed at the tip (when not editing or selecting the segment). If there is no blue dot, please correct it by following the steps for [[Image:Jct_dead_end.pngCreating and editing road segments#Fix the end-node on cul-de-sacs and dead-ends|fixing dead ends]].
=== Cul[[Image:Jct_cul-de-sacs ===sac_ex.png|left|border]]The junction indicator should be located close to the middle of the bulb and NOT near the outer edges. If the end of the segment is positioned along the perimeter of the bulb, there may be difficulty in processing client routes. Waze only considers the road fully traversed if both ends of a segment are crossed. If the end of the segment happens to be on the curb (or off of the road surface if aerials are not exactly aligned), it will be very difficult for a driver to cross the end of the road segment. With the junction in the middle of the visual road, we give a driver a good chance to cross the end of the segment no matter where they drive within the bulb. The exception to this guidance is given in the next example.{{clear}}
''See also{| class="Wikitable floatright"| [[Image: Jct_cul-de-sac_island_ex.png|200px|border]]| [[httpImage://enJct_cul-de-sac_island_ex_road.wikipedia.org/wiki/Culpng|border|200px]]|}This cul-de-sac Cul, with a small island, should be treated as a basic dead end with no loop. The island can be ignored, as there is no significant routing question for the driver once they get to the cul-de-sac article on Wikipedia]''.
A Cul-de-sac (a.kAs for placement of the final junction indicator, here we may get better results by moving the junction out from the true center and over to the outer perimeter of the central island.The shift ensures that the driver has a. Court) is a common treatment good opportunity to cross the end of a dead end street in a residential neighborhoodthe segment.{{clear}}
In almost every situationHowever, a cul-de-sac should be treated exactly as a dead end street, with the final junction node in the bulb of the cul-de-sac. : [[Image:Jct_cul-de-sac_ex.png]] If if the cul-de-sac has a very large bulb with an a large island in the middle, it may better be treated as a [[#Loops|Loop]] . A good rule of thumb is if you were standing at the size truly significant. A simple dead end should be our initial design thoughof the cul-de-sac, and can you tell that it is just a cul-de-sac? Or does it look like two different roads? If you see an island, but are not sure if it is significant, leave the Loop only used if problems with out. If "Missing Road" errors occuron the road, then add a Loop.
=== Loops ===
<gallery mode="packed-hover">
File:U-shaped Road.jpg|U-shaped road
File:Jct loop bulb.png|terminal or dead-end loop
</gallery>
Road segments form a loop when you can trace a path from a starting point around to the same point without retracing any portion of the traced path.
Loops are roads that you can enter and without turing around, end ==== Every loop must be made up at the same place you started.of three or more segments ====The important Map Editor rule we must follow is[[File: '''a road segment must ''Loop_3-part_6.jpg|right|150px]]Any loop that does not'' start and end on the same junction node'''. If follow this rule is not followed, can cause problems for the Waze routing server will have difficulty in providing routes into and out of the loopHopefully If there will be another roadway is no side-street, you must [[Map Editing Quick-start Guide#Splitting a segment|insert an extra junction node]] along the loop road which you can map, which . Many new editors will break see the loop into two pieces extra junction node(s), assume they are not needed, and avoid the problemdelete them. Please educate new editors. But if there are no interruptions to the loop and the entire loop is represented by one road segment that doubles back on itself, we have a problem
To properly handle this ====Two-segment loops====Two-segment loops create a situationcalled "same endpoint drivable segments" or "same connection segments". There are two or more ways to get from one junction node to another without going through any other nodes. They can cause a problem for the Waze app regardless of the direction, we must insert or other attributes of the segments. This is because the routing server gives your mobile app a superfluous junction list of node along IDs only, but the loop segmentapp needs to tell you which segments to drive on. The specific location does not matterIf there are two ways to get from one node to the next without going through any other nodes, but most people but it near then the Waze app might just have to guess. It might guess a detour off the halfhighway through a service road or scenic overlook. Please save Waze from this silliness. Correct two-way point of the segmentloops.
: ====One-segment loops===={{anchor|Loop_save_errors}}[[ImageFile:Jct_loop_bulbDead end loop.png|thumb|right]] One-segment or self-connected loops are often found in basemap areas. It is difficult for Waze editors to create one-segment loops. Depending on the situation, these should be converted to three-segment loops or simple dead-end roads. For more on loops on dead-end roads, please see [[Image:Jct_loop_square.pngCul-de-sac#Cul-de-sacs|cul-de-sac]]. It is important to preserve house number data on these segments.===== Fixing one-segment loops=====If you try to edit a one-segment loop, but then cannot save the changes, undo your changes and then try one of the following to fix it:
*If the loop and the road leading to it have the '''NOTE:same''' It is very easy for you or another editor to find name*#Select the loop and the road.*#Click the bridge icon that appears (one end of the loop will disconnect from the other)*#Move the now free end of the superfluous junction node, assume loop so it is truly superfluous, slightly separated*#Save*If the loop and delete the road leading to it! So if you can identify have '''different''' names*#Draw a new road segment that connects to map along the loop, even if /road junction*#Give that new road the same exact name as the loop*#Select the loop and the new road segment*#Click the bridge icon that appears (one end of the loop will disconnect from the other)*#Move the now free end of the loop so it is slightly separated*#Save*Create a parking lot, that would provide dead end road or a more "permanent" treatment of the three-segment dead-end loopas appropriate.*Fix elevations.*Confirm turns.
Here is a [http://www.youtube.com/watch?v=a7yAzG7HElw video on YouTube showing the second method].{{#widget:YouTube|id= Roundabouts and Traffic Circles ==a7yAzG7HElw}}
: [[Image:Jct_roundabout.png|frameless|right]]
Please ===Roundabouts and traffic circles===It may be tempting to use the roundabout feature to create a loop shape. Do not do this unless the loop is a roundabout or traffic circle. Roundabouts give special routing instructions, and must not be used for other purposes. To learn more, please see the [[Roundabout]] page for a full discussion of this special type of junction.
=== At-Grade Connectors grade connectors ===
: [[Image:Jct_at_grade_keep.png]]
Make sure you With exceptions, don't confuse set these segments for as ramps! And watch Watch out for all of the turns you need to restrict. For a full more detailed discussion, see the full [[At-Grade_Connectors|At-Grade Connectorsgrade connectors]] page. == Ramps == Ramps have a very specific purpose in Waze. They are intended to connect segments of Minor Highways, Major Highways, and Freeways to roads where there are no at-grade crossingsarticle.
=== How complex should Interchanges and ramps be? ===
Rule #1 is still simpler is better. So unless there An '''interchange''' is a large deviation of distance between paths at the end of a ramp (either into or out of the ramp as appropriate), a single segment connecting to a single road junction node is all that is needed. The simple existence of a painted, concretewhere two roads are connected by dedicated roadways, or grass island is called '''NOTramps''' enough of a reason to split a ramp into multiple ramps. The roads connected by an interchange do not intersect one another directly, and if they cross, the crossing is grade-separated.
: [[Image:Jct_ramp_no_split.png]]=== When to use ramps ===
Once paths at the end of the ramp deviate significantly in distance, regardless Use of the existence of any {{Ramp}} type of island, then it is time to consider multiple ramps.governed by the following rules:* [[Road types]]* [[At-grade connectors]]
: [[Image:Jct_ramp_split.png]]=== Ramp and interchange style ===
== Limited Access Interchanges ==''See also: For guidance on the proper configuration of ramps, interchanges and wayfinders, see [http:[Junction Style Guide//en.wikipediaInterchange]].org/wiki/Interchange_(road) Wikipedia article on Road Interchanges]''
When two roads meet in == Special Cases ===== Transitions ==={| class="Wikitable floatright"| [[Image:Jct_transition.png|x150px|border]]| [[Image:Jct_transition_90.png|x150px|border]]|}A transition is a limited access interchange (any situation where travel between grade separated roads is facilitated by ramps or slip roads alone), extra care must be takennon-junction depicted using a junction node.
If an exit ramp lines up with an entrance ramp, care must be taken to restrict the straight through direction to prevent "ramp-to-ramp routing" Valid examples of where the routing engine may try to take use a shortcut from the Freeway, to the exit ramp, to the entrance ramp, and back to the Freeway instead Transition node include:# Road name changes# City Limits# Road Direction changes# Part of staying on the Freeway. That motion is inefficient and may be illegal in certain jurisdictions.a [[#Loops|Loop Road]]# Speed Limit Change
'''Care must be taken Before the current house numbering system came into use, transition nodes were used to not enable all turns aid in any situation where ramps meet unless all possible flows of traffic have been considered!'''house numbering, but that is no longer required.
We also have to pay attention to There may be existing transition nodes on the '''Level''' of map for other reasons like remaining after a connecting road is deleted, inherited from the road segments since there will typically be many bridges original base map import when rivers and overpasses for any limited access interchange. If two roads cross without connectingstreams created junctions, their levels must be differentetc.
The following sections discuss some of the common Interchange designs. Note that some Interchanges As long as you are '''certain''' it is not a valid transition node, a superfluous junction node may be [[Map Editing Quick-start Guide#Delete a hybrid of these basic designs where one side or quadrant of Junction|deleted]]. Doing so will simplify the map, eliminate turn restrictions to maintain, and reduce computing resource needs. Also consider removing the interchange may differ from [[Creating and editing road segments#Adjusting road geometry .28nodes.29|geometry node]] which will replace the othersjunction node you delete, if that geometry node is not needed.
=== Diamond Interchange Roads to Nowhere ===: [[Image:Jct_diamondIn certain situations it may be necessary to add road segments that are un-drivable in order to provide accurate navigation instructions.png]]''See also: [http://en.wikipedia.org/wiki/Diamond_interchange Diamond Interchange article on Wikipedia]''
Common ==== Actual ====A valid use of this technique is at the temporary end of a freeway. As a freeway is built, it is often opened in wide open spaces where land acquisition and geography are not concernssections, up to a certain exit. If we map this Interchange design has ramps equally distributed across all 4 quadrantsas a regular freeway segment leading to a ramp segment, no announcement will be made for that final exit, no matter what we name the exit ramp.
In This can be confusing if the simplest formramp is set up as a properly signed and numbered exit, especially if a driver is traveling a long distance on this can be represented as single connections from the ramps to the surface streetfreeway. Imagine traveling down a freeway and seeing your next instruction is "turn left at Main St. Just " You would probably wonder if there was a map error since you shouldn't be sure to restrict the straight through motion from the exit ramp onto the entrance rampmaking a left turn off of a freeway.
: [[Image:Jct_diamond_simple_turnsIf we map even just a little of the future path of the freeway, this gives the routing engine a junction which will generate an "exit" instruction at the end of the freeway, thus eliminating any confusion.png]]
If Conversely, if we do NOT want an exit instruction at the ramps connect to end of a freeway, ensure there are no road segments extending past the surface street at multiple points (be sure to read [[#How_complex_should_ramps_be?|How complex should ramps be?]]final exit, we have to avoid ramp-to-ramp routing as well as illegal turns which should use another ramp. First we see ensure the final exit is the turns that must be restricted for only path out of the exit ramps:final freeway segment.
: [[Image:Jct_diamond_cplx_turns_off_L.png]] [[Image:Jct_diamond_cplx_turns_off_R.png]]
 
Then we see what must be restricted for the entrance ramps:
 
: [[Image:Jct_diamond_cplx_turns_on.png]]
 
'''Note on Levels:'''
The single surface street segment between the inner most ramps should be either raised or lowered in relation to the freeway segments depending on the actual geography at the interchange.
 
=== Cloverleaf Interchange ===
: [[Image:Jct_cloverleaf.png]]
 
''See also: [http://en.wikipedia.org/wiki/Cloverleaf_interchange Cloverleaf Interchange article on Wikipedia]''
 
In a Cloverleaf Interchange, left turns are eliminated from all movements between the Freeway and the surface street. First check the exit ramps.
 
: [[Image:Jct_cloverleaf_off_outer_turns.png]] [[Image:Jct_cloverleaf_off_inner_turns.png]]
 
Then check the entrance ramps for illegal turns.
 
: [[Image:Jct_cloverleaf_on_turns.png]]
 
The connections to the Freeway segments may be treated in two ways:
 
:[[Image:Jct_cloverleaf_options.png]]
 
# (top) we can have the inner entrance and exit ramps have their own junction nodes with the Freeway.
# (bottom) we can have the entrance and exit ramps share a single junction node with the Freeway. This allows us to eliminate the very short Freeway segment that may exist between the inner entrance and exit ramps.<br />It is best to offset this shared junction onto the Entrance ramp side of the surface street. This prevents the junction from accidentally being connected to the surface street or looking like it does. We favor the Entrance ramp side, because this would result in a slightly earlier exit instruction which is of course preferred over a late exit instruction.
 
The determining factor of which design to use will partly depend on the actual size and scale of the specific interchange.
 
'''Note on Levels:'''
The single surface street segment between the inner most ramps should be either raised or lowered in relation to the freeway segments depending on the actual geography at the interchange.
 
=== Folded Diamond ===
: [[Image:Jct_folded_diamond.png]]
''See also: Discussion of Folded Diamonds and A2/B2 Partial Cloverleafs on the [http://en.wikipedia.org/wiki/Partial_cloverleaf_interchange Partial Cloverleaf Interchange article on Wikipedia]''
 
Geography or property ownership may prevent the ability for an interchange to be constructed with all ramps evenly distributed across the 4 quadrants of the interchange. When only two quadrants are used, it is typically called a Folded Diamond (basically a sub-type of a Partial Cloverleaf Interchange). The ramps may be all on one side (as in the examples in this section) or they may be located in diagonally opposed quadrants.
 
The unique situation presented by the Folded Diamond arrangement is having both Entrance and Exit ramps terminating on the same side of the surface street. Ideally both ramps should terminate on the same junction node to permit us to easily restrict the illegal and usually impossible ramp-to-ramp movement.
 
: [[Image:Jct_folded_diamond_u-turn.png]]'
 
Like with a basic Diamond Interchange, often it will be necessary to represent the ramps making multiple connections to the surface street (Be sure to read [[#How_complex_should_ramps_be?|How complex should ramps be?]]. Restrict all non-permitted turns.
 
: [[Image:Jct_folded_diamond_off_turns_L.png]] [[Image:Jct_folded_diamond_off_turns_R.png]] [[Image:Jct_folded_diamond_on_turns.png]]
 
'''Note on Levels:''' Similar to a basic Diamond interchange, in most cases only the segment of the surface street that crosses the Freeway segments will need to be adjusted up or down.
 
=== Single Point Urban Interchange (SPUI) ===
: [[Image:Jct_SPUI.png]]
''See also: [http://en.wikipedia.org/wiki/Single-point_urban_interchange Single Point Urban Interchange article on Wikipedia]''
 
A SPUI is a very space and flow efficient design, but it takes extra attention to ensure the turns are correct. And as the name indicates, ideally there should be a single junction in the center. You may need to tweak the geometry of segments a bit off of alignment from the real physical world, but it should be minor if the interchange is a true SPUI.
 
The outer branches of the exit ramps are very much like in the case of a diamond interchange:
 
: [[Image:Jct_SPUI_off_outer_turn.png]]
 
Where things get complicated is the inner branches leading to the Single Point. You need to avoid ramp-to-ramp in two directions and a reverse flow turn. '''Note:''' The ramp-to-ramp motion to facilitate a U-Turn (the top left arrow in the image below) may or may not be allowed depending on the specific interchange. Please validate this turn.
 
: [[Image:Jct_SPUI_off_inner_turn.png]]
 
Luckily the entrance ramp restrictions are similar to the diamond interchange:
 
: [[Image:Jct_SPUI_on_turn.png]]
 
If you were to look at all the restricted turns at once, you may get the false impression that something is very wrong. But as you now know, a SPUI has almost as many restricted turns as allowed ones.
 
: [[Image:Jct_SPUI_all_turns.png]]
 
'''Note on Levels:'''
The two surface street segments (between the outer ramps and connected to the Single Point) and the 4 ramp segments connected to the single point should all be the same level, either one higher or one lower than the level of the freeway segments above/below the single point.
 
== Oddities ==
=== Offset Roads ===
[[Image:Jct_4_offset.png|left|x150px|border]]Sometimes you will find two roads which cross , where one does not quite line up exactly from one side to with the other.
There are a few things we need to look at in this situation.{{clear}}: * Do the roads actually line up in reality? If so we need to modify the junction to be a basic 4-way junction.{| class="Wikitable floatright"|[[Image:Jct_4_offsetJct_4_offset_align.png|x150px|border]]|[[Image:Jct_4_offset_align_ex.png|x150px|border]]|}:* Do the roads ALMOST line up in reality? If you were giving instructions to a person and would tell them to go straight with no mention of any slight turn or jog, then we want to make it into a 4-way junction. You may need to "split the difference" and not follow the centerline of either road to achieve this. The angles are exaggerated in this next example to show how the junction is forced to be close to 90 degrees, then we taper to the true centerlines of the roads. In practice this can be much more gradual and/or done while zoomed in very close.[[Image:Jct_4_offset_ex.png|right|x150px|border]]:* Finally, is there a true separation between the roads? Would you need to say for example "turn left then make an immediate right"? If so then we will want to leave the junction such that the two sides do not align.{{clear}}
There are [[Image:Jct_4_offset_sep_ex.png|left|x150px|border]]Since we want to avoid very short segments of road (the GPS chips in consumer devices can be very inaccurate which may make it seem that a few things we need driver skipped right over a short segment. This will result in [[Map Problems in Waze Map Editor|automated map errors]] and possible route recalculations in the client,) it may be wise to look at shift the side roads as far apart from each other as possible with them still in this situationthe proper location (along the far curb lines for a residential street for example). This will maximize the length of the short segment between the side roads.
# Do the roads actually line up in reality? If so we need to modify the junction to be a basic 4-way junction.# Do the roads ALMOST line up in reality? If you were giving instructions to a person and would tell them to go straight with no mention of any slight turn or jog, then we want to make it into a 4-way junction. You may need to "split the difference" and not follow the centerline of either road to achieve this. The angles are exaggerated in this next example to show how the junction is forced to be close to 90 degrees, then we taper to the true centerlines of the roads. In practice this can be much more gradual and/or only done while zoomed in very close.<br/>[[Image:Jct_4_offset_align.png]] [[ImageCategory:Jct_4_offset_align_ex.pngStyle Guide]]<br/># Finally, is there a true separation between the roads? Would you need to say for example "turn left then make an immediate right"? If so then we will want to leave the junction such that the two sides do not align. Since we want to avoid very short segments of road, it may be wise to shift the side roads as far apart from each other as possible with them still in the proper location (along the far curb lines for a residential street for example). This will maximize the length of the short segment between the side roads.<br />[[Image:Jct_4_offset_ex.png]] [[ImageCategory:Jct_4_offset_sep_ex.pngTable examples]]