Path Discussion View history

Revision as of 19:36, 1 March 2023 by Kartografer (talk | contribs) (added signs image)
These paths have lanes and turn instructions on them, providing accurate information to all drivers through this complex single-point urban interchange.
This is how the above example looks in the app.

A path is a map object that represents a sequence of connected, routable segments. It looks like a junction box connection without the box, and it provides some of the same functionality. Paths were developed primarily to enable better control over lane guidance, but they are also useful for customized turn instructions.

Overview

Paths were derived from junction boxes. Like junction box connections, paths:

Unlike junction box connections, paths:

  • Cannot affect routing.
    • Cannot be restricted, either fully or partially.
    • Cannot be marked as difficult turns.
    • Do not collect speed data separate from the segments that comprise them.
  • Need not fit within a 0.001° by 0.001° bounding box.
  • Cannot start and end at the same segment.
  • Can be nested one inside another, with different entering segments, different exiting segments, or both.

In addition, the segments inside a path may be cut or merged, as long as the path remains routable, but the segments at either end of the path may not be cut or merged, without deleting it. This the opposite constraint as that of junction boxes. Switching the route of a path does not disable alternate routes between the start and the end of the path (since there is no box within which this constraint may be placed), and the available routes to switch are limited to the three shortest.

Where to use

Nested paths with turn instructions and lanes provide accurate, concise instructions from southeast to west through the interchange shown above.

Paths may be used wherever far lane guidance and/or far turn instructions are needed. As of February 2023, however, no segment may be part of a junction box and a path at the same time. Therefore, one must decide which tool to use. Only junction boxes support restrictions and enhanced data collection on their connections. Therefore, JBs are the better choice where:

  • Certain multi-segment routes, like U-turns on 4-way H or # intersections, must be restricted or labeled difficult turns, and this cannot be done using simple turn restrictions.
  • Traffic moves through one or more segments at different speeds depending on its origin and destination segments.

In all other situations, use paths to set up far lanes and/or far turn instructions. The ability to choose which connections to create in an area makes paths much more flexible to use, and paths are quicker to create. Most importantly, only paths can be nested, so that one path starts within another path, ending either at the same or different segments.

Nesting

One path may start or end inside another path. This enables finely tuned turn information. For example, consider a two-lane ramp that exits a freeway toward a major road. At the intersection the ramp grows to four lanes, with two lanes turning left and two lanes turning right onto the road, and with further side streets intersecting nearby. Two paths can be made from the freeway to divide the exit lanes (and signs, if applicable) between routes that turn left at the intersection and routes that turn right. Then from the ramp multiple paths can be made to divide each of the four lanes for traffic that turns left or right on the road and then turns left or right on the side streets.

If a path starts at the same segment as another path and then ends inside that path, there is a conflict, and only the longer path's information is shown. This is true even if the paths contain different types of information, such as a voice prompt on the shorter path and lanes on the longer path, or lanes on the shorter path and a turn instruction on the longer path.

Editing

To create a path, zoom in to zoomlevel 16 (old zoom 4) or higher, select one segment where you want the path to start, then multi-select another nearby segment where you want the path to end. If there is a navigable route between them over five segments or less, the Create far turn icon will appear at the end of the second segment. Click it to create a path. If more segments are involved, or the path automatically suggested is not what is needed, and the route switcher doesn't help, select all the segments between the beginning and the end of the possible path, and then look for the Create far turn icon to create the path. If this icon is not shown, there may be a turn restriction somewhere, a segment may be part of a junction box, or the desired path may be too long.

To delete a path, click the entry segment. On the general tab, under the address fields, there is a list of Path Turns Exits. Hovering over the paths will highlight where each one goes; click the 🗑 trashcan icon to delete the path.

Effects in editor

Many simple paths grace the multi-lane turns of this downtown area.

The Paths layer in WME displays a white circled arrow with a blue fill over all segments that enter paths. This layer is visible at zoomlevel 14 (old zoom 2) and higher. When one of these entry segments is selected, at zoomlevel 17 (old zoom 5) or higher, each path is visible in green with a turn arrow where the path ends, just as with junction box connections. Paths that cross difficult and/or partially restricted turns or segments have diagonally hatched and/or yellow arrows, respectively. Otherwise, they have solid green turn arrows. Path far turns cannot be directly restricted. Partial restrictions and difficult turns cannot be edited on path far turns, only viewed. They are controlled on underlying segments and turns.

The near turns on paths cannot be disallowed, because paths must contain navigable segments. For the same reason, segments that are part of a path cannot be deleted, nor can they be disconnected from the nodes that are part of the path. In addition, the entry and exit segments of a path cannot be cut or merged, though segments in between them can. Before cutting or merging a segment that serves as the entry or exit of a path, be sure to delete the path first; otherwise, you will be unable to save your work.

When a segment in the middle or end of a path is selected, the path is not visible unless the mouse hovers over a locked element, like an end of a segment or a direction button in the information pane. Hovering over these helps editors to see which path to delete, should they need to cut, merge, disconnect or delete a segment that's not the entry segment.

Maximum length

The maximum length of paths is unknown. Staff have stated that paths are subject to the same length requirements as junction boxes, but this is no longer true. Paths of nearly four miles, within more than 0.07° of longitude between entry and exit segments, have been demonstrated successfully. This is seven times the size limit for junction boxes. The creation of long paths can be difficult, as the Create far turn icon does not reliably show while remaining at the proper zoom and panning over from entry to exit segment; there is little practical reason to create paths longer than a mile or two.

Far turn menu

The far turn menu for paths contains four elements: Voice prompt (grayed out), Instructions, Switch Route (where applicable), and Difficult Turn (grayed out). Even though the voice prompt dropdown is grayed out in the main far turn menu, it can be added in the Instructions sub-menu.

Just as with turns through nodes, voice prompts, turn instructions and TTS can be customized for far turns through junction boxes and paths.

Please note: Although turn instruction information is added by hovering over the exit arrow of the far turn, in most cases it is applied at the entrance. Think about what the driver sees at the entrance when adding turn instruction information to paths and JBs.

Voice prompt

This set of turn instructions provides a continue voice prompt past a divided road toward an Interstate.

If a voice prompt override is added to a far turn, then all internal Waze selected voice prompts are removed, and the voice prompt is announced at the first node of the path or JB connection. As of February 2023 (except for in some in-car interfaces like Android Auto) the name of the exit segment is displayed and spoken by default, just as the turn arrow tooltip indicates, even there is a named segment before it inside the path/JB.

If a voice prompt override is added to a far turn, and lane guidance has also been set up where the voice prompt is given, the lane guidance will be displayed with the voice prompt. Make sure to check the lane guidance when adding a voice prompt (and anything else, really) to far turns, and add far lanes if necessary.

Instructions

A voice prompt can also be added in the Instructions panel. If all other fields in this panel are blank or unchanged from their default values, the voice prompt override will function alone, just as if it had been added directly from the turn arrow tooltip. On paths the voice prompt can only be changed in the Instructions panel.

All other elements of the Instructions panel function together (the various visual instruction fields and TTS). They are usually given at the first node, like the voice prompt, but if the criteria of the 50-meter rule are met, they are given at the next full turn instruction. They require a full turn instruction to have an effect; if the driver is not told to turn, exit, continue, etc. where this information would be given, no visual instructions can be displayed there, and no auditory instructions can be spoken.

TTS

Even though the TTS (text to speech) box will show the name of the exit segment in gray, this name may not actually be what's spoken. If the name of the exit segment is required in TTS, be sure to confirm it by clicking the TTS field (turning the text from gray to black), then clicking Apply, before saving the far turn instruction.

Usage of far turn instructions

Use far turn instructions to match each exit sign (or section of a sign) at exits like these, so that only the relevant information is shown and spoken. Note that the far turn arrow highlighted in the bottom left is not the same as the near turn arrow highlighted in the next pane, even though they appear in the same place with different segments selected.
A voice prompt on this far turn provides a "keep left" instruction instead of the default "turn left, then turn right".

Where they are used, turn instructions should be applied to simple, node-based turns rather than far turns (JBs and paths), if possible, to avoid rework if the junction box or path needs to be deleted in the future. Reasons for customizing far turn instructions include:

  • Multiple signs are displayed for a single turn, with each sign pertaining to the next turn (see example at right). Customize the visual instructions and TTS, but usually not the voice prompt, so as not to suppress the next turn instruction.
  • A sign pertains to a straight movement through a divided road intersection, and a continue straight instruction is necessary. Customize the visual and TTS instructions, and add a Continue voice prompt.
  • One or more divided roads meet at a roundabout, and normal instructions are desired and/or there are different signs at different entrances that pertain to the same exit. Customize the visual instructions and TTS, and/or add turn right/continue/turn left/U-turn voice prompts, as necessary.
  • Segments connect in an intersection in such a way that, with realistic geometry and node-based turn instructions, incorrect voice prompts are given. Customize the far turn's voice prompt.

Conflicts

Far turn voice prompts conflict with all near turn (single node) voice prompts within the connection. If a voice prompt is set on any of the near turns that make up a connection, the far turn's voice prompt has no effect.

Far turn visual and/or TTS instructions only conflict with near turn instructions where they are given (usually on the first node, or on the first turn where the far lanes 50-meter rule is active). Visual and/or TTS instructions can be used on the other turns in paths or junction box connections. Be sure to remove conflicting information from near turns when working with far turn instructions.

For more information on turn instructions, see the turn instruction page.

Far lanes

Simple lane guidance works well in many places but not all of them. Far lanes were developed in order to provide editors greater control over unusual and complex lane situations. Far lanes may be added to the far turns in the lanes tab for any segment that enters a junction box or path, unless that far turn includes a segment of a roundabout.

For an extended introduction on far lanes, click Expand.

Standard lane guidance is inadequate.
Consider the first image to the right, looking northward. Using standard lane guidance, the drivers who turn right to SR-161 E would see the right turn lane highlighted from this set, and the drivers who turn left to either SR-161 W or I-270 S would see both left turn lanes highlighted, no matter which direction their route went after the left turn. The heuristic algorithm for divided-road intersections is unable to combine these sets of lanes, because the turn angles don't meet the criteria. The resulting behavior is not particularly helpful nor accurate, because (1) it is a single intersection, with all turns controlled by the same set of traffic lights, and (2) people who turn left need to be in one of two specific lanes, since those lanes split immediately after the turn. With far lanes these two problems can be solved. To make the lane guidance work here as a single intersection, a far turn must be added from the junction with the right turn to the junction with the left turn (either by drawing a junction box over them or creating a path), the distance between these two junctions must be less than 50 meters, and the lane guidance at the junction with the left turn must be removed.
This configuration can tie both junctions together, but it doesn't differentiate between the two left lanes, which is also needed here.
If our goal is only to tie the lane guidance together as a single intersection, we would only need one far turn, and it would look like the image to the right, with both left turn lanes checked on the far turn and a slight arrow specified, to match how these lanes look at the intersection.
With two far turns, we can get proper lane guidance for each left turn separately.

However, that doesn't solve the second problem, the need for specific lane guidance to the two left turn lanes that split. Therefore, instead of one far turn to the ramp segment that turns left from the intersection, we create two longer far turns that end past it at the SR-161 W ramp and the I-270 S ramp. Then we check the boxes for the left lane and second-to-left lane, respectively. This will give specific, comprehensive lane guidance for everyone who turns left to either SR-161 W and I-270 S, and to those who turn right to SR-161 E.

What's more, far lanes can be used to provide clarifying, advance lane guidance at this intersection for all other traffic going north, since there is another nearby intersection to the north with turn-only lanes. This helps, for example, people going to I-270 N to know that they should be in the second lane from the right when going through the first intersection, then after that they should use that right lane to turn right. Without this clarification, they will simply see and hear "use the right lane to turn right" and may take the wrong turn. The final result, with turn instructions added to both left turns is shown in WME and in the app.

These paths have lanes and turn instructions on them, providing accurate information to all drivers through this complex single-point urban interchange.
This is how the above example looks in the app.

Far lanes can be added by rank 4 and higher editors. The first phase of their development was to enable them for junction boxes, which is known as far lanes phase 1 or FL1. The second phase of their development was the release of the paths feature, which is known as far lanes phase 2 or FL2. Although junction boxes and paths have some differences, far lanes work identically whether in a path or junction box connection.

Far lanes have a few effects that can enhance lane guidance, described in the following subsections.

Preferred

One of the most important effects of far lanes is the ability to map preferred lane guidance. This type of lane guidance shows drivers that they should use a particular lane or lane(s) that are a subset of the lanes involved in a turn. For example, there may be two lanes that turn left at an intersection, and then the two lanes split immediately in two different directions. If a driver's route is to turn left where there are two left turn lanes, then immediately keep right using one of those two lanes, the driver would prefer to be in only the second lane from the left, as taking the leftmost lane would require the driver to quickly switch lanes. This is shown in the animated example to the right for the left turn to I-270 S.

Notice that for the turn to I-270 N only the second lane from the right is given, but it is not shown with a full instruction; instead this lane is a view only lane that reads "Continue straight" below it. This is also a preferred lane, but it isn't shown at the same place as a turn instruction. In addition, notice that the left turns are given 500 feet ahead of the driver, with the same lane picture. These different behaviors of far lanes are more fully explained in the next subsection.

Display behaviors

The lane or lanes added to a far turn are treated in one of four ways in the Waze client:

  1. They are "view only", silently shown at the end of the entry segment with "continue straight" text.
  2. They are shown after the end of the entry segment, along with the next visible, audible turn instruction, as part of a combined, single intersection.
  3. They shown immediately at the end of the entry segment with a visible, audible turn instruction.
  4. They are not shown at all.

View only (> 50 meters to next turn)

View only non-straight lanes can be confusing.

If there is no turn instruction for a far turn on the first node after the entry segment, and there is either:

  • No turn instruction on any subsequent nodes of the far turn within 50 meters past the first node, or
  • Lane guidance before the next turn instruction,

and the far lanes are either:

  • Not straight, or
  • Straight, with the "View only" setting applied,

then these far lanes will be displayed at the end of the entry segment with "Continue straight" under them.

This can be useful to provide clarifying, advance notice to drivers, telling them "don't turn here, but keep going in this lane, then turn at the next intersection." This is how these far lanes are used in the first far lanes example, for traffic going to Executive Pkwy and I-270 N.

However, this can also cause unexpected results, since a turning lane arrow with "continue straight" under it often appears self-contradictory, and if this behavior happens where the turn is coming up in the same intersection, it could even lead people to miss their turn. Be sure to understand this effect, and if single-intersection far lanes behavior is desired instead, read on.

Single-intersection heuristic (< 50 meters to next turn)

Similar to the heuristic used to combine the lane guidance for separate turns through H and # intersections, there is a different heuristic used with far lanes to ensure that a complete lane picture is shown at every turn through an intersection with multiple nodes and segments. The turns at multiple nodes in a single intersection are tied together, but with less stringent requirements and better control by editors. This is especially useful where an intersection has at-grade connectors, there are multiple short segments to the next turn, or its geometry is skewed too much from perpendicular to meet the requirements for H and # heuristic to work. Another advantage of this far lanes heuristic is that the lanes are only set on the entry segment, and the full lane picture is visible in WME in one place.

With lanes removed from the next segment after the entry segment, and the distance kept at less than 50 meters, single-intersection lane guidance works properly.

The single-intersection heuristic is applied to both left turns toward SR-161 W and I-270 S in the first far lanes example. It is also applied in the example to the right. After lane guidance was removed from the next segment, the driver simply sees one left turn instruction in the proper place.

Far lanes are only combined for an intersection, or "pushed" past the first node to the next turn, if all of the following criteria are met:

  • No turn instruction is given at the first node, just as with view only far lanes.
    • Voice prompts and view & hear straight lanes are considered, on both near and far turns.
  • The distance to first node that has a turn instruction within the far turn must be less than 50 meters (164 feet).
  • No lane guidance may be present on the segment immediately before the instruction.
If you check a far lane box here...
... you should remove this lane guidance here.

If far lanes are pushed, any visual turn instruction, TTS or voice prompt set on the far turn is also pushed to the location of the next turn. This can cause some unexpected results, so be sure to understand where an instruction will be displayed when using far lanes.

A segment may not support both the non-far-lanes divided-road heuristic combination and far lanes in the same direction. If you decide to add far lanes to an intersection that has the older heuristic combination, be sure to remove any subsequent lane guidance on the median segment and, if applicable, past the AGC. The far lanes must be on the first segment that enters the intersection in order to work properly.

Immediate, full instruction

The left turn is part of the same intersection, and the far lane for it is shown where the left turn happens. The far lanes for the right turns are shown immediately at the end of the entry segment, while the straight lanes are never shown.

Just as with standard lane guidance, if a full turn instruction occurs (either because the next segment is not the best continuation, a voice prompt is used to force an instruction, or view & hear straight lane(s) are set on the far turn) at the end of a segment, any far lanes that this turn comprises are shown with the turn instruction.

The lanes tab in the example to the right shows two standard right turn lanes followed by lanes set on several different far turns. If a route follows any of the right far turns, such as to I-10, the applicable right turn lane is shown at the A end of the selected segment.

Not shown

If there is no turn instruction for a far turn on the first node after the entry segment, and there is either:

  • No turn instruction on any subsequent nodes of the far turn within 50 meters past the first node, or
  • Lane guidance before the next turn instruction,

and the far lanes are straight with the "Waze default" setting applied, they will not be shown.

In the example above, the three straight far lanes that continue on Veterans Blvd are not shown in the app for movements eastward through the junction box. This is the same behavior as expected with standard lane guidance. In general, setting far lanes that aren't shown to drivers only happens in junction boxes, since with paths you can choose which individual connections to make, and there is no point in making a path that has no effects in the app.

Editing notes

This lane guidance is correct, even if the left lane is not applied to a near turn. If the U-turn had been allowed without a far lane, no lanes would be shown with any turn from this segment.
The loopy route above has no lane guidance assigned to it, resulting in an error. If you see this tooltip after saving, your lanes are invalid and must be fixed before they will show in the app.
If you check a far lane box here...
... you should remove this lane guidance here.

Far lanes may only be added to far turns on junction boxes and paths. There are a few things to take note of:

  • As of February 2023 there is no automatic assignment of lane directions to far turns as to near turns; the lane arrows must be set manually.
  • Set far lane arrows based on what the driver sees around the end of the segment selected; far turn arrows merely show which routes the turn information applies to, not where the lanes are shown in the app during the drive.
  • Make sure that every lane is checked somewhere, and every route through the end of the segment has lanes assigned either on near or far turns.
  • After saving, make sure that the lane guidance does not have any error indicators, especially if not all lanes are assigned to near turns. Any possible "escape" from lane guidance will result in an error that invalidates the entire set of lane guidance for all the turns from the segment.
    • The fix for such "escape" lane errors is to "capture" them with lane guidance, either using shorter paths or assigning more lanes to turns.
  • It is not always necessary to assign every lane to a near turn, but it is good practice where possible, for the above reasons.
  • As of March 2023 the LaneTools script indicates errors in lane guidance if not all lanes are assigned to near turns, but this is inevitable in many situations with turn lanes.

Further far lane resources

For more information on lane guidance, see the lanes page.