Wayfinder

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Revision as of 06:52, 26 September 2017 by Nagamasa (talk | contribs) (Terminology)

A wayfinder is a junction that instructs users on a certain road how to continue on that same road, in situations where it may be unclear, and there would otherwise be no instruction. Most wayfinders use short or "stub" segments to specify instructions, and some use turn instruction overrides as well. This page will explain criteria, configuration and different use cases of wayfinders.


Terminology

A travel lane is a lane which is long enough that a naïve driver might consider it a long-distance lane. For our purposes we will clarify this as any lane which;

  1. before nearing the exit, is neither striped nor signed as a departing lane over a significant length (approximately ¾ a mile, or its full length, whichever is shorter), and
  2. has not just started within a mile before the exit.

A continuation path or continuation is the group of lanes after the junction which continue to be the same road as they were before the junction. (In the following example, the lanes which continue to be I-47)

Lane definitions.png

Criteria

75split.png
An instruction should be given where it is unclear how to continue on the highway on which one is driving. Usually this is a keep instruction, but sometimes, as explained below, it should be a continue instruction. A wayfinder is warranted in the following cases:
  • The continuation path on a controlled-access highway or freeway, when an exit is present on the right side, has at least two fewer travel lanes after the exit than before it;
  • The continuation path on a controlled-access highway or freeway has fewer lanes than, the exit path after the fork;
  • The continuation path on a controlled-access highway or freeway has the same number of lanes as the exit path after the fork, and the continuation path is unclear;
  • The continuation path on an uncontrolled highway, or when an exit is present on the left side of a controlled-access highway or freeway, has at least one fewer travel lane after the exit than before it;
  • The continuation path consists of a single lane; or
  • Other conditions exist that may suggest a fork, rather than an exit (use your better judgement, and discretion) -- for example:
    • The physical roadway itself forks or diverges with no clear straight-ahead direction;
    • The road which appears to be straight ahead is not the actual continuation;
    • Signage and striping do not clearly provide all expected "exit" indications, or do so inconsistently; or
    • Signs are present with arrows pointing left and right but no sign clearly establishes the continuation.

In these cases, we need to use a wayfinder configuration.

Configuration

Multiple methods exist for forcing instructions on highway continuations, such as matching the road type of both outgoing segments even where it creates a discontinuity or falsely using an alternate name on the non-continuation side to match the continuation side. Since Waze editors have the ability to create turn instruction overrides, the preferred approach is to use correct road types and alternate names, stubs named to match signage and turn instruction overrides where necessary.

S-in-s-out.png
Each wayfinder configuration will have one in segment and (usually) two stub or continuous out segments.
  • Each stub segment should be 19.69 ft (6 m) long. This is long enough so it will not cause routing problems, but it is short enough to suppress display of the names.
  • Unless a continue instruction is given the out segments should have a turn angle of 10°-15° off of the mid-line on opposite sides of each other, consistent with the geometry for freeway forks. This will allow for easy identification in WME, but still look seamless in the client app.


To configure the wayfinder,

  • If the numbered/signed exit is on the right:
    • For an exit, use a keep left TIO into a named freeway stub for the continuation, and a standard ramp for the exit.
    • For a freeway fork, use a named freeway stub on both sides with an exit right TIO on the right side, unless "keep right" seems more appropriate for the numbered exit.
  • If the numbered/signed exit is on the left:
    • For an exit, use a named highway stub of the same type as the in segment for the continuation, and an "exit left" TIO for the exit followed by a ramp.
    • For a freeway fork, use named highway stubs on both sides, and use an "exit left" TIO on the left side, unless "keep left" seems more appropriate for the numbered exit.


The following table assumes that the highway is a freeway:

Exit direction Type Left OUT configuration Right OUT configuration Example
Right Exit Continuation side
"keep left" TIO →  named fwy stub  fwy 
Exit side
 ramp 
WFexitright.png
Right Fwy fork Continuation side
 named fwy stub  fwy 
Exit side
"exit right" TIO (where appropriate) →  named fwy stub  fwy 
WFforkright.png
Left Exit Exit side
"exit left" TIO →  ramp 
Continuation side
"keep right" TIO →  named fwy stub  fwy 
WFexitleft.png
Left Fwy fork Exit side
"exit left" TIO (where appropriate) →  named fwy stub  fwy 
Continuation side
 named fwy stub  fwy 
WFforkleft.png

Continue instruction

With the creation of turn instruction overrides, continue instructions can be given. Where a keep or exit instruction would be misleading, a continue instruction can be given, as explained here. The turn instruction override page also has other use cases for the continue instruction on highways, most of which are not wayfinders (i.e. it is clear how to continue on the highway, but an instruction is nonetheless useful). Where a continue instruction is used to supplement a wayfinder, the geometry should match the instruction, so the deviation of the continuing highway should be close to 0°.

Segment naming

Keep these basic principles in mind:

  • If turn instruction overrides are not used, the OUT segments must both be the same type (either  Freeway ,  Major Highway ,  Minor Highway , or  Ramp , as explained below).
  • If turn instruction overrides are not used, each OUT segment must have a name different than the IN segment.
  • OUT segments should be named with the information displayed on the roadway signs.
    • However, if this would leave an OUT segment with the same name as the IN segment, use a turn instruction override instead, and use a standard highway segment rather than a stub.

If the continuation is signed, and a wayfinder is warranted,

  • If the continuation sign contains the name or shield of the continuing road, do not use "to" at the beginning of the name of the OUT segment. e.g., a freeway fork where one side is the continuation of the same freeway (the user is already on the road, not going "to" it). Most wayfinders will fit this criterion.
    • If the name of the continuation is included but is not listed first on the sign, move the name of the continuing road to the beginning of the segment name. (e.g. In this wayfinder the highway you are on now, and continuing on is I-275, so the segment name should be "I-275 N / I-74 E / US-52 E / Cincinnati".)
  • If the continuation sign does not contain the name or shield of the continuing road, then the road name should begin with "to".

If the word "TO" is explicitly included on the continuation sign,

  • Wayfinder To BGS.png
    Move the shields or names affected by the "TO" to the end of the segment name after a slash (/). (The example BGS shown is for the continuation of I-80, which leads to I-280, with a control city Morristown.)
    • If any included control cities or road names correlate only to the roads affected by the "TO", then those control cities or road names should be moved after the "/ to [road(s)] /" on the segment name.
      • Wayfinder To WME.png
        If Morristown is served by I-280 and not by I-80, the continuation segment should be "I-80 / to I-280 / Morristown".
    • If any included control cities or road names correlate to the roads not affected by the "TO", then those control cities or road names should remain in place before "/ to [road(s)]".
      • If Morristown is served by I-80, the continuation segment should be named "I-80 / Morristown / to I-280".

If the continuation is not signed, and a wayfinder is warranted,

  • If the OUT segment is a continuation of the same road, use a turn instruction override and a standard highway segment.
  • If the OUT segment is an exit, it should be named following the guidelines for an unsigned exit.
  • If the OUT segment is a short continuation of the same road leading to another road, name the segment starting with "to" followed by the name of the road to which the continuation leads, following these guidelines:
    • No BGS To exit.PNG
      Where the wayfinder is just before, but not at, the termination of a road, so the continuation OUT segment is named for the road that the continuation leads to at the termination. However you still must travel for a short distance on the continuation of this road until those exits/termination.
      No BGS To exit zoom out.PNG
      Our example here is a wayfinder on US-1-9 N (Truck), the left OUT is the continuation, however the right OUT also continues on the same road until it intersects with SR-440, with an exit to SR-440 S along this short segment. There are no roadway signs for any of these forks, or exits/terminations. The OUT segment here would be named "to SR-440 S / Communipaw Ave", and the SR-440 exit will be named following the unsigned exit guidelines. However it may be appropriate (if there are no House Numbers, or other on ramps past this wayfinder before it reaches the exit, to leave this entire portion with no name, and the instruction will inherit the name of the next road to which you are going.

Examples

# Continuation sign Continuing road name Rule Waze road name
Wayfinder I-10 BGS.png
Wayfinder I-10 WME.png
context image
1 I-10 E / New Orleans Business District I-10 E Matches - do not use "to" I-10 E / New Orleans Business District
# Continuation sign Continuing road name Rule Waze road name
Wayfinder continuation TO I-71.png
Wayfinder 471 close.png
Wayfinder 471 context.png
2 I-71 N / Columbus I-471 N Does not match – use "to" to I-71 N / Columbus
# Continuation sign Continuing road name Rule Waze road name
Wayfinder continue last BGS.png
Wayfinder 275 closeup.png
Wayfinder continue last WME.png
3 I-74 E / US-52 E / I-275 N / Cincinnati I-275 N Included but not first – move to beginning I-275 N / I-74 E / US-52 E / Cincinnati
# Continuation sign Continuing road name Rule Waze road name
BGS image WME image context image
4 name
# Continuation sign Continuing road name Rule Waze road name
image image image
5 name