Questions on default speed limits for Indiana

Communities United States
1

Hey there

Hey there, I am currently working on this: https://wiki.openstreetmap.org/wiki/Default_speed_limits

The legislation for default speed limits in Indiana is getting me a headache, perhaps you can help me. There are a few things I want to ask, maybe there is someone here who is from Indiana and knows about the road laws a bit:

(source)
What is an INDOT freeway, how would it be obvious to a road user that he is on an INDOT freeway (so that he knows the max speed he is allowed to drive) and how is it tagged in OSM?

(source)
How would it be obvious to a road user that he is on a highway that is the responsibility of the Indiana finance authority (so that he knows the max speed he is allowed to drive) and how is it tagged in OSM?

(source)
In Indiana, what is a federal highway and how would it be tagged in OSM? What is a state highway and how would it be tagged in OSM?

2

I’m from Indiana and I’m pretty sure I’ve driven on all of these, but I’m not familiar with the legal definitions of them all. I answered your questions as best as I can though. I’ve included example roads that I think illustrate the three types of highway, but they might not be the only way that they should be mapped.

  1. I think an INDOT freeway just means that the road is built as a limited access dual-carriageway road, with grade-separated interchanges.
    Example: https://www.openstreetmap.org/way/174092516#map=14/41.1152/-84.9198

  2. From what I can find the only roads the Indiana finance authority is responsible for is the toll road, which is Interstate 80/90. If you don’t know about this the toll road was leased by the state to a company. https://www.in.gov/indot/2413.htm
    Example: https://www.openstreetmap.org/way/163602572#map=13/41.7497/-85.5191

  3. I’m pretty sure A federal highway just means part of the federal highway system, and I think State highway refers to state roads. Both of which can look very similar, but from all the examples I can think of a state road will always have intersections, although they might be exceptions to this.
    Example: https://www.openstreetmap.org/way/155051239#map=13/41.3098/-85.2015

I’m not really sure how all of these should be tagged as I usually get to confused with how the different classes of roads should be tagged so I just let them remain.

I hope that this helps you, let me know if anything doesn’t make sense, or if you still have questions.

3

If I remember correctly from last year’s visit to Indiana, the speed limits were signposted regularly on Indiana Toll Road (I80/90). See the third picture from the bottom on this page for an example. For your purpose you might not want to regard this as a default but rather a special speed limit tagged to the highway.

4

Thank you, jgon6 :slight_smile:

Hmm, this would conflict with §9-21-5-2 (7), though, which sets a default speed limit of 60 for dual-carriageway roads. (Also, I thought term “freeway” is the same as a “trunk” in British English, an almost-expressway which is not completely access-controlled.)

Hmm, odd, the toll road is an interstate and §9-21-5-2 (3) and (4) already deal with interstates. On the other hand, the limits set in (6) are exactly the same as (3) and (4), so I guess §9-21-5-2 (6) can be ignored because it is already covered.

So, which kind of roads are part of the federal highway system and state highway system? Or perhaps it is easier to answer which roads are not? And of course, the final question here would be, if there is any way to find this out using existent OSM tags. E.g. for interstates, it is easy:

ref~"^I "

I can partly answer the first question by myself: After a bit of research, it appears that

  • Interstates, US routes, Other Principal Arterials, Strategic Highway Network (STRAHNET), Major Strategic Highway Network Connectors and Intermodal Connectors are federal highways (source)
  • Indiana state highways are, well, just those: List of state roads in Indiana

So then, perhaps it is possible to find the letters with which these refs start for these kind of roads? Interstates start with I, US routes start with US, Indiana state highways with SR (or IN?? Is this a tagging mistake? But no idea bout the others.

On the other hand, perhaps it is safe to assume that any road that does not have a ref is neither part of the federal, nor of the state highway network? That would indeed be the easiest solution.

5

I think you are right about the federal and state highways having a ref tag. As for the State road prefixes, Looking around on the map I see some mapped with SR and others mapped with IN. I’m pretty sure they are just tagged inconsistently(Perhaps a future project). The Indiana Wiki page says they should be tagged with IN, but the Wikipedia list they link to has them all listed with SR. I looked at how the state lists them and a lot of the time they just print a number, but they all ways seem to be listed with State Road, if they have a prefix.

As for testing based on if they have a ref tag or not I think that should work, Federal and state highways should all have ref tag on either them or as part of their relation. If they don’t have one and are part of either network then they would be missing the tag, but my cursory look around the state shows that they all seem to be pretty good.

6

Hm, why IN though? We can’t just make things up. In any case, that looks like a project to me. Discuss and decide on one consistent tagging, explain it in the wiki and change everything to what has been decided.

Well, that only leaves the case for the mysterious “INDOT freeway” open.

7

IN is the postal abbreviation for Indiana. Most state roads are prefixed like that. Ohio uses SR, Michigan just uses M, there may be other exceptions.

8

So, it’s Wikipedia that got it wrong?

9

I don’t know. It could be that there is a reason for the SR convention on wikipedia or it could just be the choice somebody made way back when. Same for the prevalence of IN on OSM (except there is vague agreement in the US in general to use the postal abbreviations as prefixes there).

10

Hi, I just discovered this thread and it spurred me to make my first-ever forum post. :slight_smile:

For the purpose of this section, I’d assume a “federal highway” is any U.S. route – that is, INDOT-maintained routes that are numbered at a federal level by AASHTO. For funding purposes, there are other federal classification systems like STRAHNET and the National Network, but “federal or state highway” is clearly worded in opposition to “county or township highway”. So I’m pretty sure ways with refs beginning with US, IN, or SR would be 60 mph, while virtually any other surface road would be 40 mph.

(Several years ago, I went up and down eastern Indiana tagging county and township roads with refs beginning with CR, C-, TR, or T-, but I was overzealous in doing so. I was mistaken in thinking Indiana counties and townships number and signpost their roads the same way Ohio counties and townships do. Some counties do number their roads on a grid, but to turn it into a systematic abbreviation would probably be incorrect.)

Except for some regional colloquial usage, “freeway” in American English is equivalent to “motorway” in British English. A freeway is almost always completely access-controlled and may be tolled. A partially access-controlled highway is generally called an “expressway”. Note that the official names of these highways may contradict their classifications. Many freeways outside California are named “Something Expressway”, for example, but that doesn’t make them expressways.

Wikipedia’s policy is to use the officially correct prefix, and by that standard it’s correct. By contrast, OSM uses the postal abbreviation in most states, regardless of official or colloquial usage. This practice was influenced by some rendered maps by MapQuest and Mapbox, long since defunct, that used regular expressions to choose state-specific route markers. (MapQuest still displays state-specific route markers, but not based on OSM data.)

Both IN and SR are both in use throughout the state and always have been. However, I’d very much like for us to transition to SR in Indiana – and for renderers and routers to support route relations. Please see this talk page for more background.