Mapping missing Exit numbers in USA

[pratikyadav]

Task objective

Mapping missing exit numbers on motorways in USA by adding ref tags on motorway_junctions

Imagery source- crosscountryroads.com

Background

There are over 52,000 highway=motorway_junction in USA with almost 9000 of them missing ref tag representing the corresponding exit number.

Map of highway=motorway_junction without ref tag [as on 30 march 2016]

Focus area

For now following 9 states based on mapillary coverage have been selected as priority areas.

• California
• Florida
• New Jersey
• Maryland + DC
• Pennsylvania
• Washington State
• Colorado
• Texas
• Illinois

Mapping Workflow

Locate highway=motorway_junction nodes missing exit numbers (represented by blue dots in TMS layer) and add ref=* for corresponding exit number using combination of Department of Transportation(DoT) exit number documents, mapillary images and other sources.

Gist for detailed workflow with examples
Last updated 6th April

Changeset comment and source

Comment-> Adding missing exit numbers https://github.com/mapbox/mapping/issues/165
Source-> Bing;Mapillary;Wikipedia

Team

@mapbox/team-data

Duration

Current estimate is 2 weeks

Resources

• Custom TMS layer to locate missing exit numbers - click this link to load in JOSM

tms[22]:https://api.mapbox.com/v4/pratikyadav.3b94b1a9/{zoom}/{x}/{y}.png?access_token=pk.eyJ1IjoicHJhdGlreWFkYXYiLCJhIjoiMTA2YWUxNjRkNmFmZGQ4YzAxZWFiNDk0NDM1YjE1YjAifQ.4P6N5dNmA_WQXd3BsJvu5w

• Large blue dots represent missing ref tags
• Small red dots represent already mapped motorway_junction with the label representing exit number.
  • Mapillary coverage layer - click this link to load in JOSM
    tms:http://d2munx5tg0hw47.cloudfront.net/tiles/{zoom}/{x}/{y}.png
  • Mapillary Photos
  • State Department of Transportation(DoT) exit number documents.
  • Wikipedia
  • Cross Country roads
  • Aaroads

[gyllen]

There is a more updated version of mapillary coverage in our vectortiles. You can find more information here http://blog.mapillary.com/update/2015/05/27/vectortiles.html

The endpoint is https://d2munx5tg0hw47.cloudfront.net/tiles/{z}/{x}/{y}.mapbox

[talllguy]

@pratikyadav exciting workflow here! It looks like your link above for State DOT exit numbers is only for California. For Maryland, there isn't a public point based feature representing exit points that I know of. However, you can query on the state's open data portal to look for route segments where the station_description (segment description) include the word "Exit" to find any segments with their exit number in the attributes.

Here is a Gist I made from that query.

[talllguy]

Following up from my comment above. Based on the data in the Gist, you can analyze the segments and determine the Exit Number for all Maryland State maintained roads.

[talllguy]

One other useful thing, you can check your work with the CheckAutopista2 tool. Here's an example with Interstate 83. Red dots indicate no exit numbers are present.

[pratikyadav]

@gyllen This is great!! Mapillary coverage is going to be an important source in this mapping project. 🚀

@talllguy The gist for Marryland looks great. Nice work 👏 🚀

We took CheckAutopista2 for a small trial before coming to this final workflow. Indeed, the tool is great, easy to use and can speed up the productivity. The only issue is its dependency on overpass-turbo api. We faced some problem when multiple people were sending request from the same IP address. We are looking for ways to overcome this issue and include CheckAutopista2 asap in our workflow.

[planemad]

Observations

• The workflow is pretty good, made some updates on formatting https://gist.github.com/planemad/6d79bbe29aa31fa83e1497b9910d59fa
• Reviewed four major interstates in CA in two hours
  • Almost all the junctions with missing refs did not have an actual number based on the C-DOT source and Mapillary. Most had a noref=yes, for others added it. These were usually exits to rest areas.
  • Found only one newly constructed exit that was missing. Found the number in a news video.
  • Overall the coverage of exit numbers looks excellent
  • The common issue in existing data was some motorway exits were tagged on motorway_link branching from another motorway_link rather than from the motorway itself
  • Mapillary helps but is scarce outside cities, often only one side is available.
  • The CDOT listing of exit refs were most useful for data verification

[ramyaragupathy]

While working on California highway CA 24, came across this ref tag. As per the tag information there should be two exits, one to the left and the other to the right. But I see only one road branching out from this point.
Could someone please help understand how this works?

https://www.openstreetmap.org/node/1215636490/history

cc @planemad @pratikyadav

[planemad]

@ramyaragupathy just checked it out. This is basically the end of CA-24 and both the roads at the fork are each considered an exit, one heading southbound on I-680 and one northbound on I-680.

This is exactly what is mentioned in the caltrans list.

cc @1ec5

[planemad]

What would be the best way to add multiple refs to an exit?

Example: Exit 434A, 434B in SF on US-101

Various options ares:

• ref=434A;434B
• ref=434B|434A
• ref=434

cc @1ec5 @ajashton

[planemad]

Is it common to have multiple physical exits with the same ref? Should the missing ones for the weigh station exit be added?

http://k1wiosm.github.io/checkautopista2/?id=69364&lat=38.7015&lon=-121.3173&z=15

[jinalfoflia]

I have posted the diary with the above contents.

/cc @planemad @pratikyadav

[1ec5]

What would be the best way to add multiple refs to an exit?

ref:left and ref:right would be reasonable, I think. The wiki recommends a different approach using a semicolon, but both schemes could be used concurrently.

Is it common to have multiple physical exits with the same ref?

It’s common for opposing directions of a divided highway to have separate physical exits with the same ref. So both northbound and southbound I-75 might each have an exit 28A and 28B at the same interchange; exit 28A might go eastbound from northbound I-75 but westbound from southbound I-75.

Regarding missing exits in California, be sure to verify the presence of number signage on Mapillary. I just spot-checked U.S. 101 in the San José area, and some exits have refs on OSM despite being unnumbered on signage.

For example, this northbound exit node has a ref. As I discovered driving down this stretch yesterday, this particular exit is numbered going southbound, but not going northbound. I think cases like these, where there’s an official exit number but no signage, should be tagged with unsigned_ref to avoid causing navigation software to use a number that the user can’t find.

[talllguy]

I believe the ref:left and ref:right are the old way, where junction nodes were solely used for routing directions. From what I've seen with the Mapzen routing engine, the router can infer right or left at the fork, based on the tags on the downstream highway link, if they exist. Conversely, if there aren't downstream destination:* tags, I suppose it'd be best to leave the ref:left and ref:right.

For the sign in the wiki:

[pratikyadav]

Recapping our work from last week (04/03 - 04/08) -

We added tags on 202 motorway junctions that included: 1. exit numbers i.e ref=* , 2. missing exit numbers noref=yes at the rate of ~16 tags per hour while checking for references on Mapillary Imagery, official DOT documentation, and Wikipedia. Based on this run, and progress, our estimate is to be able to complete adding exit tags in all 9 states in one week. Here is a full breakdown of what we did:

• Avg. mappers involved: ~6
• Days spent mapping: 4
• # of nodes added: 202
• # of nodes per hour/person: 2
• States Covered (US): California, Washington, Illinois, Florida

[planemad]

Created an Overpass query to get a better sense of the stats:

• Total motorway_junction edited by team in last two weeks: 179
• Exits with a ref: 49 (green)
• Exits with noref: 135 (red)
• Exists with ref and noref (invalid?): 5
  

@pratikyadav mismatch with the stats from osm-query is probably because it used a bbox rather than the USA polygon with the above overpass query. The 5 exits with both ref and noref needs a recheck.

[rickmastfan67]

You guys might want to fix your 'changeset' comment for this project. You're linking people to Issue #164, instead of here to #165. Had to look around here to get to the correct place after seeing several changesets with the incorrect issue link in them.

[pratikyadav]

@rickmastfan67 Thanks for flagging this. I have changed the comment and notified the team to use 165 instead of 164.

[pratikyadav]

Project Summary

We finished the mapping of exit numbers for these 9 states using Checkautopist2 and here are some observations-

• Most of the highways (motorways) are in good condition in terms of exit numbers.
• We reviewed 220+ motorways in these 9 states and added 63 missing exit numbers using mapillary images.
• We spotted 219 motorway_junction with no relevant exit number, and thus assigned noref=yes to them.

Break-down-

• Avg. mappers involved: ~6
• Days spent mapping: 7
• # of nodes added: 282 (63 ref=* + 219 noref=yes)
• # of nodes per hour/person: 2

OSM Diary -> https://www.openstreetmap.org/user/jinalfoflia/diary/38501

@mapbox/team-data great work 🚀

Shout-out for @k1wiosm for checkautopista2 and @talllguy for flagging the tool here. 👏 🚀