Who decides who gets to have kids?

[Max Rockatansky]

That's the unfun answer though.  Unless you want to see the California Division of Highways fundamentally not understand the child route concept and drive the AASHO executive secretary up the wall.

https://www.gribblenation.org/2022/11/establishing-numbering-conventions-of.html?m=1

[hbelkins]

There are many instances of the first digit of 3di's (within a state) being assigned in numerical order. Low to high: S to N and W to E. When new 3di's pop up between existing ones, all bets are off.

I was thinking about I-81's offspring. Of course, I-181 got taken over by I-26, but you have I-381 and I-581 in Virginia. I-81 doesn't have any more odd-numbered offspring until you get to Watertown/Fort Drum -- where any of the other numbers would have worked, but instead of recycling one of them (and, of course, by that time, 181 was gone) they opted for 781.

[Beltway]

There are many instances of the first digit of 3di's (within a state) being assigned in numerical order. Low to high: S to N and W to E. When new 3di's pop up between existing ones, all bets are off.

I was thinking about I-81's offspring. Of course, I-181 got taken over by I-26, but you have I-381 and I-581 in Virginia. I-81 doesn't have any more odd-numbered offspring until you get to Watertown/Fort Drum -- where any of the other numbers would have worked, but instead of recycling one of them (and, of course, by that time, 181 was gone) they opted for 781.

The one in Virginia that is out of sequence is I-564. But that is said to be because 164 and 364 already had primary iterations in 1956 and policy is to not use the same number as an existing primary route.

[kphoger]

Can you imagine using I-410 the long way around the south end of San Antonio as an alternate to I-10 through town?  I've used I-410 several times, but always as an alternate to I-35 instead (or else a link between I-10 and I-35).

[1995hoo]

Can you imagine using I-410 the long way around the south end of San Antonio as an alternate to I-10 through town?  I've used I-410 several times, but always as an alternate to I-35 instead (or else a link between I-10 and I-35).

I've thought the same about I-485 around Charlotte, which works fine on the northern side as a bypass of I-85 closer to the city or to connect between I-85 and I-77, and which also works fine on the southwestern side to connect between I-85 and I-77 (or as a western bypass to I-77 through the city).

But the southern/southeastern side is insanely far out of the way. Heading south on I-85, say from Greensboro to Atlanta, it's 18.5 miles if you go straight through close to the city, it's 19.3 miles around via the northern side of I-485, but it's 48.7 miles if you go around the southeastern side. Even if you're heading to southbound I-77 towards Columbia it's still way out of the way to use that part of I-485.

[dlsterner]

Can you imagine using I-410 the long way around the south end of San Antonio as an alternate to I-10 through town?  I've used I-410 several times, but always as an alternate to I-35 instead (or else a link between I-10 and I-35).

I've thought the same about I-485 around Charlotte, which works fine on the northern side as a bypass of I-85 closer to the city or to connect between I-85 and I-77, and which also works fine on the southwestern side to connect between I-85 and I-77 (or as a western bypass to I-77 through the city).

But the southern/southeastern side is insanely far out of the way. Heading south on I-85, say from Greensboro to Atlanta, it's 18.5 miles if you go straight through close to the city, it's 19.3 miles around via the northern side of I-485, but it's 48.7 miles if you go around the southeastern side. Even if you're heading to southbound I-77 towards Columbia it's still way out of the way to use that part of I-485.

Likewise.  I routinely use the "northern" part of I-485 when traveling south on I-85 to I-77 south.

[Mapmikey]

There are many instances of the first digit of 3di's (within a state) being assigned in numerical order. Low to high: S to N and W to E. When new 3di's pop up between existing ones, all bets are off.

I was thinking about I-81's offspring. Of course, I-181 got taken over by I-26, but you have I-381 and I-581 in Virginia. I-81 doesn't have any more odd-numbered offspring until you get to Watertown/Fort Drum -- where any of the other numbers would have worked, but instead of recycling one of them (and, of course, by that time, 181 was gone) they opted for 781.

The one in Virginia that is out of sequence is I-564. But that is said to be because 164 and 364 already had primary iterations in 1956 and policy is to not use the same number as an existing primary route.

Don't think this is accurate...

VA 295 still existed when the 1958 interstate number requests were made, as were most of the 2-digit numbered interstates requested (VA 64, 66, 68, 81, 85 - all but 68 were renumbered in March 1958; VA 77 and VA 95 were already gone by then).

Virginia requested I-364 in 1958, though VA 364 hadn't been born yet.

Given that they commissioned I-195 while VA 195 in Southampton County still existed and VA 385 existed when I-385 was proposed, I'm pretty certain Virginia just renumbered state routes for interstate designations of the same number.

On the flip side, they did not renumber VA 311 when US 311 came back (though a CTB meeting had it as a topic), nor have they renumbered VA 121 for US 121.  So if I-87 ever gets to Virginia, will they renumber the short VA 87 way on the other side of the state...?

[Revive 755]

And the case of surrounding states with I-94? Low in Michigan (I-194) and Illinois (I-294), mid in Minnesota (I-394, 494, 694), high in Wisconsin (I-794, 894)

Illinois was going to have an I-494 but it died.

At one time there were plans for the Lake Freeway in Wisconsin to extend all the way down to the Edens in Chicagoland.  In theory this could have lead to using 794 since Illinois had 194 (replaced when I-90 was moved from the Eisenhower to the Kennedy), 394, and 594 (now I-190) as state routes with the possible intention of going for full interstate designations later.

[SkyPesos]

Can you imagine using I-410 the long way around the south end of San Antonio as an alternate to I-10 through town?  I've used I-410 several times, but always as an alternate to I-35 instead (or else a link between I-10 and I-35).

I've thought the same about I-485 around Charlotte, which works fine on the northern side as a bypass of I-85 closer to the city or to connect between I-85 and I-77, and which also works fine on the southwestern side to connect between I-85 and I-77 (or as a western bypass to I-77 through the city).

But the southern/southeastern side is insanely far out of the way. Heading south on I-85, say from Greensboro to Atlanta, it's 18.5 miles if you go straight through close to the city, it's 19.3 miles around via the northern side of I-485, but it's 48.7 miles if you go around the southeastern side. Even if you're heading to southbound I-77 towards Columbia it's still way out of the way to use that part of I-485.

Then there's I-275 in Cincinnati, which is a terrible bypass for I-75 on both sides. East loop works somewhat as an I-71 bypass, though.

For full beltways, I notice auxiliary numbers of x0 and x5 interstates getting prioritized over other interstates, even if the alignment looks otherwise. I-270 in Columbus's north-south segments are longer than east-west, which an I-x71 number would fit better.

[Quillz]

I've always felt that for concurrencies (like the mentioned 20/59), it has to do with the overall directionality or what the control cities are. Like if you've got a diagonal concurrency that is trending northward, or maybe the next major city is northeast, you'd number the auxiliaries based on the odd parent (in this case, 59).

It's when you've got cases like the 80/90 concurrency where it just seems to be a bunch of numbers get submitted, one gets picked. (In those cases, I'd generally go with the lower parent, but I don't know if that's how the actual decisions went).

[SeriesE]

Can you imagine using I-410 the long way around the south end of San Antonio as an alternate to I-10 through town?  I've used I-410 several times, but always as an alternate to I-35 instead (or else a link between I-10 and I-35).

If there's an east-west Interstate that goes through the metro, the beltway would've been the child of that one IMO

(I-74 ends in the center)
I've thought the same about I-485 around Charlotte, which works fine on the northern side as a bypass of I-85 closer to the city or to connect between I-85 and I-77, and which also works fine on the southwestern side to connect between I-85 and I-77 (or as a western bypass to I-77 through the city).

But the southern/southeastern side is insanely far out of the way. Heading south on I-85, say from Greensboro to Atlanta, it's 18.5 miles if you go straight through close to the city, it's 19.3 miles around via the northern side of I-485, but it's 48.7 miles if you go around the southeastern side. Even if you're heading to southbound I-77 towards Columbia it's still way out of the way to use that part of I-485.

Then there's I-275 in Cincinnati, which is a terrible bypass for I-75 on both sides. East loop works somewhat as an I-71 bypass, though.

For full beltways, I notice auxiliary numbers of x0 and x5 interstates getting prioritized over other interstates, even if the alignment looks otherwise. I-270 in Columbus's north-south segments are longer than east-west, which an I-x71 number would fit better.

[TheHighwayMan3561]

In the Twin Cities, since 494/694 bypass both cities on their routes, it makes more sense to make those x94s. MN 294 was in use as a state highway when the interstates were commissioned, so that's probably why they started with 494.

[Beltway]

The one in Virginia that is out of sequence is I-564. But that is said to be because 164 and 364 already had primary iterations in 1956 and policy is to not use the same number as an existing primary route.

Don't think this is accurate...
VA 295 still existed when the 1958 interstate number requests were made, as were most of the 2-digit numbered interstates requested (VA 64, 66, 68, 81, 85 - all but 68 were renumbered in March 1958; VA 77 and VA 95 were already gone by then).
Virginia requested I-364 in 1958, though VA 364 hadn't been born yet.
Given that they commissioned I-195 while VA 195 in Southampton County still existed and VA 385 existed when I-385 was proposed, I'm pretty certain Virginia just renumbered state routes for interstate designations of the same number.
On the flip side, they did not renumber VA 311 when US 311 came back (though a CTB meeting had it as a topic), nor have they renumbered VA 121 for US 121.  So if I-87 ever gets to Virginia, will they renumber the short VA 87 way on the other side of the state...?

There is I-381 and VA-381 as well. I realize there are a few of them. But the widespread policy seems to be avoiding duplications.

I have heard about I-364 but have always wondered if it was official or just tentative.

[Molandfreak]

The one in Virginia that is out of sequence is I-564. But that is said to be because 164 and 364 already had primary iterations in 1956 and policy is to not use the same number as an existing primary route.

Don't think this is accurate...
VA 295 still existed when the 1958 interstate number requests were made, as were most of the 2-digit numbered interstates requested (VA 64, 66, 68, 81, 85 - all but 68 were renumbered in March 1958; VA 77 and VA 95 were already gone by then).
Virginia requested I-364 in 1958, though VA 364 hadn't been born yet.
Given that they commissioned I-195 while VA 195 in Southampton County still existed and VA 385 existed when I-385 was proposed, I'm pretty certain Virginia just renumbered state routes for interstate designations of the same number.
On the flip side, they did not renumber VA 311 when US 311 came back (though a CTB meeting had it as a topic), nor have they renumbered VA 121 for US 121.  So if I-87 ever gets to Virginia, will they renumber the short VA 87 way on the other side of the state...?

There is I-381 and VA-381 as well.

Even Caltrans would not consider that a duplication...

[DTComposer]

The one I don't agree with is I-605 in California. I get that the vision was part of a multiple-loop setup with I-405, but to me it functions more like an odd x10 - the same way 110 and 710 are used (even though they were designated later).

In fact, I could justify current 110, 710, 605, 57, and 71 being numbered as 110, 310, 510, 710, and 910. /fictional

[Mapmikey]

I have heard about I-364 but have always wondered if it was official or just tentative.

It was officially requested by VDOH.

Go here: https://grmservices.grmims.com/vsearch/portal/public/na4/aashto/default

Then go here, which has AASHO rejecting I-364.  Further in is the map VDOH submitted:  https://na4.visualvault.com/app/AASHTO/Default/documentviewer?DhID=324d1f19-37e6-ea11-a98a-ff9beffbfef8&hidemenu=true

I had forgotten, but I-364 was also floated for the Hampton Roads 3rd Crossing in one of the VTrans 2035 documents which no longer appear to be available even at archive.org. 

[Henry]

Some 3di's have become a real head-scratcher, such as one in Savannah: Why I-516 when 116 and 316 could've been used?

Also, you have I-395 and I-695 (plus, potentially, I-195) in both Baltimore and Washington, DC, which means a missed opportunity to get an I-995 in one of those two cities. I've always wondered why that is?

[Beltway]

I have heard about I-364 but have always wondered if it was official or just tentative.

It was officially requested by VDOH.
Go here: https://grmservices.grmims.com/vsearch/portal/public/na4/aashto/default
Then go here, which has AASHO rejecting I-364.  Further in is the map VDOH submitted:  https://na4.visualvault.com/app/AASHTO/Default/documentviewer?DhID=324d1f19-37e6-ea11-a98a-ff9beffbfef8&hidemenu=true
I had forgotten, but I-364 was also floated for the Hampton Roads 3rd Crossing in one of the VTrans 2035 documents which no longer appear to be available even at archive.org. 

Neither of those links work

[freebrickproductions]

Some 3di's have become a real head-scratcher, such as one in Savannah: Why I-516 when 116 and 316 could've been used?

NGL, part of me wouldn't be too surprised to find-out that I-116 and I-316 are/were reserved by GDOT in case they needed them for any other freeway spurs off of I-16 to the west.

[Mapmikey]

I have heard about I-364 but have always wondered if it was official or just tentative.

It was officially requested by VDOH.
Go here: https://grmservices.grmims.com/vsearch/portal/public/na4/aashto/default
Then go here, which has AASHO rejecting I-364.  Further in is the map VDOH submitted:  https://na4.visualvault.com/app/AASHTO/Default/documentviewer?DhID=324d1f19-37e6-ea11-a98a-ff9beffbfef8&hidemenu=true
I had forgotten, but I-364 was also floated for the Hampton Roads 3rd Crossing in one of the VTrans 2035 documents which no longer appear to be available even at archive.org. 

Neither of those links work

Hmm...the first link definitely works.  Not sure why the 2nd one didn't.  If you succeed with the 1st link put route designation as INTERSTATE and the state as VA in the search boxes to the left.  The 1958 CORRESPONDENCE INTERSTATE (2) is the one.  Here is the submitted map:

[Road Hog]

I think in Little Rock's case, I-30 was the first 2di to be substantially completed and so it got first dibs in planning with I-430 and I-630 (I-530, the old US 65/167, came much later but originated off of I-30). I-440 was first planned around 1980.

[Beltway]

Hmm...the first link definitely works.  Not sure why the 2nd one didn't.  If you succeed with the 1st link put route designation as INTERSTATE and the state as VA in the search boxes to the left.  The 1958 CORRESPONDENCE INTERSTATE (2) is the one.  Here is the submitted map:
http://www.vahighways.com/mapscans/i364.jpg

So what are they saying? Someone drafted that sheet, printed it out, and someone wrote "464" in ink as if to ... change? correct an error?

I also don't understand the Downtown Tunnel and Berkely Bridge being included. The Yellow Book of 1955 showed gaps there with three spurs ending short. The facility didn't meet Interstate standards and was owned by a toll authority who would be responsible for expanding it if and when they decided. They weren't responsible for an I-464 connection.

It wasn't until 1978 that VDH&T took it over and brought it into the Interstate system and obtained 90% federal aid authorization for the expansion.

[Mapmikey]

The second link has a letter from VDOH acknowledging that 364 will be re-designated as 464.

[Beltway]

The second link has a letter from VDOH acknowledging that 364 will be re-designated as 464.

Server Error
404 - File or directory not found.
The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.

[Duke87]

I've often wondered how it's decided which interstate gets to be the "parent' when there are multiple routes to choose from.

They get paternity tests and then Maury Povich shouts out, "I-59, you are the father!"