Interstate numbers that will likely never be used

[sturmde]

You got a point. States seem to favor lower 3-di designations. 9xx almost seems to be out of necessity (GA being an exception)

.
California's future I-905 and Louisiana's umarked I-910 disagree?  (CA has no 705?  LA has no 710?)

[Mr. Matté]

And Maine would be glad someday to see an I-98 built from Bangor to Calais that would take over I-395 and provide the Maritime Link to NB 1 and the New Brunswick/Nova Scotia freeway systems that would connect Boston to Halifax much better than I-95 to NB 2 does.

No, per the troll/sockpuppet on Wikipedia whose vandalism I reverted (and then had the troll/sockpuppet file a frivolous WP:ANI against me), that will be Maine State Route 395.

[SkyPesos]

For 3di, most 9xx won't be used.

8xx: mostly won't be used, but some that I could see being used in the future, in addition to the currently used ones, are 870 (Columbia Bypass), 864 (VA 288? After all, 864 is 288*3), 875 (Chattanooga Eastern Bypass).

7xx: like with 9xx, it's unlikely.

5xx: For some reason, states love to use 5xx over 1xx or 3xx for 3di spurs, which means that 25, 45 and 70 are the only x0 and x5 without a 5xx 3di. Only one that have a possibility to be a future interstate is 570.

I made a chart of odd 3di, and there's more 7xx than I thought. Note that I excluded a bunch of shorter 2di than what's on the bottom of the chart.

[CoreySamson]

I made a chart of odd 3di, and there's more 7xx than I thought. Note that I excluded a bunch of shorter 2di than what's on the bottom of the chart.

Small note, while it is not complete, Interstate 369 does exist on signs in Texarkana right now, so I'd put it in "yes".

[GaryV]

I-194 is signed in Michigan

[NWI_Irish96]

46, 48, 50, 52, 54, 56, 58, 60, 62. Too close to similar US routes.

I don't know, somewhere out there is a city with a really stupid football team that might have same numbered interstate and US routes really close together.

Go Bears!

[Scott5114]

28, 34, 36, 38. I don't think this would really fit anywhere between existing routes.

You do realize that how the grid is set up, all of these could theoretically fall within North Carolina...right?

What about my fave, I-220?

Why would I-220 be on a chart of odd 3dis?

[SkyPesos]

28, 34, 36, 38. I don’t think this would really fit anywhere between existing routes.

You do realize that how the grid is set up, all of these could theoretically fall within North Carolina...right?

Those numbers could work on US 74 Asheville to Wilmington or US 72 Memphis-Chattanooga.

46, 48, 50, 52, 54, 56, 58, 60, 62. Too close to similar US routes.

US 46 is not in its grid position, so an I-46 could work. I have I-46 on the southern I-87 in one of my fictional maps. I have I-48 on Joplin-Wichita on a fictional map, but that corridor isn't even 4 laned, so it most likely wouldn't be an interstate in real life. I-56 or I-58 could be used on the Bluegrass Pkwy in KY. I-62 could go on US 460 in VA if for some reason, the state wanted to revive the old southern alternative of I-64 as a new interstate. On my fictional map, I have I-62 on I-70 between Cove Fort and Green river, with I-70 rerouted on I-80 west to SF.

[JayhawkCO]

28, 34, 36, 38. I don't think this would really fit anywhere between existing routes.

You do realize that how the grid is set up, all of these could theoretically fall within North Carolina...right?

Those numbers could work on US 74 Asheville to Wilmington or US 72 Memphis-Chattanooga.

Also something like US82 between Lubbock and Fort Worth.

Chris

[WillWeaverRVA]

Given the current status of the grid, what are numbers you never see getting used, either due to geographic challenges, lack of any significant population centers, or too close to a similarly numbered US highway (which hasn't stopped WI or NC  )

Here's what I came up with.

East/West

6, 18, 28, 34, 36, 38. I don't think this would really fit anywhere between existing routes.

46, 48, 50, 52, 54, 56, 58, 60, 62. Too close to similar US routes.

98. No population centers large enough to warrant an interstate.

North/South

1. The coastlines of California, Oregon, and Washington are pretty rough terrain for an interstate.

9. I would like an interstate in central Oregon but US 97 seems to do just fine. Other than Bend, no huge population centers.

13, 21, 23, 31. No significant population centers where these would fit in the grid.

51. Too close to US 51

You are making too many assumptions that people would honor the grid.  I-99 shows that this isn't always the case, and that the grid itself isn't a necessity.

That's very true. It's why I left off 3. Isn't there a proposal to have a grid violating I-3 in Georgia?

There is, but thankfully that I-3 proposal doesn't look like it will ever see the light of day.

[kalvado]

98. No population centers large enough to warrant an interstate.

There was some flirting with "rooftop highway" idea in upstate NY connecting I-87 Ilattsburgh and I-81 in Watertown.
Not sure how big of a chance that idea stands.
https://www.adirondackalmanack.com/tag/rooftop-highway

[Rothman]

98. No population centers large enough to warrant an interstate.

There was some flirting with "rooftop highway" idea in upstate NY connecting I-87 Ilattsburgh and I-81 in Watertown.
Not sure how big of a chance that idea stands.
https://www.adirondackalmanack.com/tag/rooftop-highway

Every couple of years, NY wastes taxpayer money by giving it to a consultant to copy the last study done that says it isn't worth the cost.

It won't happen.

[hbelkins]

400, 412, and 425. 

[KCRoadFan]

400, 412, and 425. 

I disagree about 425 - I think that would be the perfect number for the Northwest Parkway and the southernmost section of the US 36 freeway (aka Denver-Boulder Turnpike). Colorado users, what do you think?

By the way, E-470 and C-470 would, of course, be I-470, in my imaginings.

[SkyPesos]

400, 412, and 425. 

I disagree about 425 - I think that would be the perfect number for the Northwest Parkway and the southernmost section of the US 36 freeway (aka Denver-Boulder Turnpike). Colorado users, what do you think?

Not a Colorado user, but I have 425 in mind for Powers Blvd (CO 21) in Colorado Springs if it gets upgraded to a full freeway. For US 36 Denver-Boulder, I have it as an extension of I-270 (that could be I-170 or 370 if you're really picky about the 3di guidelines), and I-470 for the Northwest Parkway, along with CO 470 and E-470.

[JoePCool14]

To add another specific 3DI to the list, I don't think we'll see a I-420 make a comeback at this point. Just seems too ripe for sign theft at least right now.

I also don't foresee an I-911 and not just because of I-11 being the way it is.

[Revive 755]

6, 18, 28, 34, 36, 38. I don't think this would really fit anywhere between existing routes.

* As mentioned by others, I-6 could be used in southern Texas.  Northern Florida could also be a far future possibility if something such as a new Tallahassee - Gainesville - Dayton Beach corridor were to be developed.

* I-18:  Plenty of space between I-10 and I-20 for an I-18 to eventually pop up.

* I-28, I-34, and I-38:  Possible for North Carolina or another future corridor (such as Memphis - Huntsville - Chattanooga) between I-20 and I-40.

* I-36:  North Carolina already tried to use this one.

46, 48, 50, 52, 54, 56, 58, 60, 62. Too close to similar US routes.

Given the number of similarly numbered US routes and interstates in close proximity these days, I don't think assumption is valid.  I'm recalling a news article a few years ago mentioning a possible I-54 for US 54 in Missouri.

98. No population centers large enough to warrant an interstate.

I wouldn't rule out this one being used for WI 29 some year.

13, 21, 23, 31. No significant population centers where these would fit in the grid.

While I think one of these may not be used, there are places they could pop up if growth continues in the southwest.

Texas could try for an I-31 northward from Austin some year in the future.

51. Too close to US 51

Not if it gets used for a north-south route in Iowa, Arkansas, or Missouri.  There could always be far future upgrades of US 63, US 65, or some part of the MO 13 corridor that gets upgraded to an I-51.  Even the Avenue of the Saints could theoretically become I-51.

[OCGuy81]

To add another specific 3DI to the list, I don't think we'll see a I-420 make a comeback at this point. Just seems too ripe for sign theft at least right now.

I also don't foresee an I-911 and not just because of I-11 being the way it is.

Yet we DO have both a US and an Interstate 69. I feel those must be prone to some theft. 😂

[Revive 755]

I made a chart of odd 3di, and there's more 7xx than I thought. Note that I excluded a bunch of shorter 2di than what's on the bottom of the chart.

* I-130 seems to have been considered for the Texarkana area prior to I-49 being built.

* I-740 might qualify as formerly planned".http://www.kurumi.com/roads/3di/i740.html#740ar

* 755 was a "State Route 3di" like 364 in all but one document I have seen.  It may qualify as an unsigned State Route 3di - I recall seeing MoDOT use the number a few times for the ramps at the I-55/I-44/Truman Parkway interchange long after the original freeway died.

* 735:  Wasn't there was a blog post somewhere a couple years back that had this as a State Route 3di for one of the unbuilt freeways in the KC area?

[SSR_317]

To add another specific 3DI to the list, I don't think we'll see a I-420 make a comeback at this point. Just seems too ripe for sign theft at least right now.

I also don't foresee an I-911 and not just because of I-11 being the way it is.

Yet we DO have both a US and an Interstate 69. I feel those must be prone to some theft. 😂

I've mentioned this here before, but it bears repeating. I once saw a great t-shirt a few years back worn by some wag out at the Indianapolis Motor Speedway. It had a graphic of the I-69 shield with the caption, "I-69, do you?"

[achilles765]

I low key hope we leave 47 alone. It's the only 1- or 2-digit number never used for US or Interstate routes

I would not be upset about renumbering IH 45 from Galveston to Dallas as IH 47...
and make IH 69 into IH 45.

[WillWeaverRVA]

Interstate 100. 

Well...

[1995hoo]

^^^^^^

In the same vein, this used to be in downtown DC (it's been removed) and bears other numbers mentioned in this thread. Picture from AARoads.

[roadman65]

Yup, Caltrans will never upgrade CA 1 to I-1 and I-50 will never be used, although I 5hink the overlaps with I-35, I-435, and I-470 should be made I-50 like US 41 was made I-41.

[Joe The Dragon]

Interstate 420
Interstate 666

sign theft may be an issue with them