Rjgambrel/Proposal about Motorways and Expressways Version 2
This is staging area for revised proposal. Following are steps to take:
- Replace content of current 4.1.1 (Proposed /Tagging guidelines / Motorways) with new text pointing to this page
Following is text to go on the official page
Proposal
This is a proposal to update the original motorway/expressway approach which was published in the main wiki page. This is a set of amendments to the original proposal that clarifies what is new or changed. It may be helpful to refer to the current Minnesota/Minnesota highway classification wiki page while reviewing this page.
Note that, relevant to this proposal, the main wiki page has two sections (4 Proposed) and (5 Agreed guidelines). The current main wiki page with regard to section 4 is essentially empty while section 5 has the main text that is being amended. The text on the page you are reading is essentially proposal text. In some cases the text is entirely new, and in other case it involves minor changes to existing prose in section 5.
In this document, all "proposal" text will be bolded and italicized. Text which is considered non controversial or is unchanged is unadorned. For deletions, the original text will be struck out.
Major change summarized
After publication of the first version of the agreed guidelines for motorways and expressways on January 26, 2022, a lively discussion was held in both talk-us and in Slack. (To view the first version, simply refer to the agreed guidelines as currently published in sections 5.1.1, 5.1.2, 5.1.5, 5.2.1, and 5.2.2. These are the various motorway and expressway sections of section 5.)
The discussion culminated in a survey published (February 17, 2022) asking reviewers to weigh in on specific currently-mapped-as-motorway-islands in Minnesota. A complete summary of that discussion and conclusions can be seen at this page: Minnesota/Minnesota highway classification/Motorway island survey results. That page is important as it addresses the only significant issue that was raised during the lengthy discussion after the agreed guidelines were published. That issue concerned the original guideline that, in essence, allowed motorway islands to be any "length". Refer to that survey results page. Based on those results the remainder of this page details a set of amendments to the original agreed guidelines. These amendments comprise version 2 of the motorway/expressway guidelines.
Amendment 1 (section 5.2.1.1)
The current motorway islands in the results table (with IDs such as US2a) will be classified as shown in the Type column of that table.
A statement to that effect will be included in section 5.2.1.1 if this proposal is agreed.
Amendment 2 (section 5.1.1.1)
The following changes would be made to the second paragraph:
If a motorway island is part of an otherwise trunk highway (both of these are based on the current OSM tagging) then the motorway island should be kept as is as long as it meets the US physical definition of a motorway. The rationale here is that the highway departments of the state and/or local governments have determined that traffic volumes and/or traffic safety considerations have warranted the upgrade to the physical properties of that section of the highway. The premise also is that these islands have been correctly mapped by OSM mappers. This section provides additional guidance.
If a section of highway appears to meet the US physical definition of a motorway and it is an "island", use the following guidelines to determine whether to categorize it as a motorway or trunk. (Note that while there may be instances of motorway islands that are parts of primary or lesser highways, none were encountered so far, so "trunk" is used here.)
| 1 | If the candidate has three or more grade-separated interchanges it should be categorized as motorway | motorway | |
|---|---|---|---|
| 2 | If the candidate has two grade-separated interchanges it should be classified as motorway unless: | motorway | |
| a | It is discussed in a forum such as Slack and the consensus is it should be a trunk (e.g. MN7a, MN13a, MN36b, MN51a) | trunk | |
| 3 | If the candidate has only a single grade-separated interchange, it should be classified as trunk unless: | trunk | |
| a | It is actually part of (connected to) a larger motorway island (see for example: MN36a), or | motorway | |
| b | In addition to the grade-separated interchange, it also has multiple bridges separating its traffic from other highways (e.g. US169i, MN65a, MN65b), or | motorway | |
| c | It is discussed in a forum such as Slack and the consensus is it should be a motorway (e.g. MN15c) | motorway | |
Note that all apparent motorway islands that were classified as trunk were ~5km or shorter. On the other hand all agreed motorway islands had no minimum length. So the primary determinant of classification was the number of grade-separated interchanges, not length.
Amendment 3 (section 5.1.1.2)
Revise the second paragraph as follows:
As for motorway islands, motorway spurs should be kept as is as long as they are part of an otherwise trunk highway. A motorway spur meeting the US physical criteria that exists, or is created in the future, is acceptable in Minnesota if it connects to a motorway network. An example is a motorway leaving the Twin Cities metro area that peters out and becomes a trunk highway until it reaches some regional center. If the part of the highway "beyond" the motorway spur should be trunk and the spur meets the physical criteria of being a motorway, then it is appropriate to leave the motorway as mapped or, in the future, map it as a motorway if it meets the physical criteria of being one.
Amendment 4 (section 5.2.1.1)
The table should be carefully updated to include the specific motorway vs trunk recommendations in the detailed motorway analysis.
The mechanical changes to the table will be done after this proposal is agreed.
Amendment 5 (section 5.2.2)
The prose prior to the table will be changed as follows:
The highway segments currently tagged with expressway=yes do not meet the criteria for being an expressway. Specifically there are numerous at-grade intersections and there are no grade-separated interchanges. The tagging should be removed.
The highways currently identified as "maybe" actually also meet the criteria of being motorway islands. Tag each of those segments as
highway=motorway.
Bottom line: there are no road segments in Minnesota that meet the requirements of being labelled expressways. The following chart adds a column to the one already provided above summarizing the agreed guidelines.
The following chart details specific places where expressway=yes should be used in Minnesota:
After the proposal is agreed, a chart will be inserted here. It will consist of rows for each existing motorway-island that have been deemed to be trunk instead of a motorway.