I have noticed on various road forums and even road-related Facebook pages where people would state: an even-prefixed 3-digit interstate has to be a loop or a beltway type deal. Or it has to connect with the same interstate at both ends. I just wonder where that comes from?
i bring it up as I saw this today. There was talk about a northern portion of I-680 becoming I-880 in Iowa and a comment said "shouldn't it be an odd number b/c it doesn't reconnect with I-80?"
https://www.wowt.com/content/news/Northern-tier-of-I-680-to-be-renamed-I-880-563078321.html
From the FHWA it says this:
QuoteConnecting Interstate routes and full or partial circumferential beltways around or within urban areas carry a three-digit number. These routes are designated with the number of the main route and an even-numbered prefix. Supplemental radial and spur routes, connecting with the main route at one end, also carry a three-digit number, using the number of the main route with an odd-number prefix.
By looking at that statement I would say as long as both ends of a even-prefixed 3-digit interstate connect to another interstate, an even number is allowed. So why do people and even fellow road-geeks believe it?
And here's an excuse to post a pic:
(https://live.staticflickr.com/4542/38700216072_833120512f_c.jpg) (https://flic.kr/p/21XNHWG)
Ideally, an even number should be used when the roadway is linking two interstate highways, whether it be the same interstate highway at either end (I.E. a beltway, bypass, etc.), or another interstate highway (I.E. a connector).
An odd number should be used if it's leaving an interstate highway, and linking to an area / route that isn't another interstate highway (I.E a spur route to link one metro into the interstate system).
It could go either way for 880. It's circumferential, not radial, with regard to Omaha (which means even), but it's also almost perfectly a straight line (which means odd).
I tend to think it should be Odd 3DI when the Parent is only "touched" once, but that view is at least partially colored because that is how they are designated in IL
In Illinois: 255, 270, 280, 290, 294, 474 all touch their Parent twice (255, 270, and 280 need the continuation of the route into neighboring MO and IA to accomplish this). 155, 172, 180, 190, 355 all touch their Parent once
By the idea that designations should be Even 3DIs when both endpoints are on the Interstate System, then 155 and 355 in IL should probably be 455 and 655. Supposedly 455 was considered for 355 at one point, even
Future 490/O'Hare Ring Tollway will endpoint at Parent I-90 and I-294, so it will be the first Even 3DI in IL that only touches its Parent once
Going from your Pic...PA is messed up with 376 and 476...376 is more like a Loop for I-76, touching the Parent twice, and I-476 is more like a Spur North/South from I-76, touching the Parent only once
Quote from: 1 on October 14, 2019, 07:35:14 PM
but it's also almost perfectly a straight line (which means odd).
Counterpoint: I-475 (GA) is nearly a straight line, but wouldn't make any sense at all with an odd first digit.
All of Ohio's 3di are even numbers. Only I-270, I-275, I-470, and I-480 are either full beltways, or (at least) meet its parent on both ends.
Quote from: Hot Rod Hootenanny on October 14, 2019, 08:06:49 PM
All of Ohio's 3di are even numbers. Only I-270, I-275, I-470, and I-480 are either full beltways, or (at least) meet its parent on both ends.
Toledo's 475 endpoints on I-75, both ends, too
I-440 in Arkansas doesn't connect to 40 on both ends, though it is a beltway.
I-430 runs from I-40 to I-30, I-630 runs from I-430 to I-30.
There is a tendency for even digit numbered routes to connect back to their parent but out here in California that trend is non-existent. A good example is the I-80 family of highways in California:
- I-280 doesn't even connect to it's parent but does by proxy to I-880 and I-680
- I-480 connected to it's parent but didn't loop back to it.
- Likewise I-680 and I-880 touch their parent route I-80 but definitely aren't loops.
Interestingly though I-405 and I-805 do loop to/from I-5 whereas none of the odd number child routes do. I-215 does loop to I-15 but that route was intended to be I-15E.
That guideline used to be honored more than it is now.
Example: long ago, the announced plan was to redesignate I-540 in NC as I-640 once it was completed; but that idea is now dead. The benefit of following the system is probably overshadowed by the drawback of renumbering a freeway.
I-680 to I-880 in Iowa is a bit of a different case in that the renumbering purpose is to decrease driver confusion. I think, in an alternate universe, if that segment had been originally numbered I-780 there would be no pressure (other than some roadgeeks) to "correct" it to 880.
One exception that comes to mind is I-526, which is a partial circumferential beltway around Charleston and as such should probably have received an even first digit. It’s not like SC was going to run out of even x26 numbers, either.
Quote from: kurumi on October 15, 2019, 12:55:38 AM
That guideline used to be honored more than it is now.
Example: long ago, the announced plan was to redesignate I-540 in NC as I-640 once it was completed; but that idea is now dead. The benefit of following the system is probably overshadowed by the drawback of renumbering a freeway.
And also, AFAIK there are no plans to renumber I-520 (GA/SC) even though it now reconnects with its parent, presumably for the same reason.
Quote from: Mergingtraffic on October 14, 2019, 07:04:42 PM
I have noticed on various road forums and even road-related Facebook pages where people would state: an even-prefixed 3-digit interstate has to be a loop or a beltway type deal. Or it has to connect with the same interstate at both ends. I just wonder where that comes from?
It varies by state. Some states only use and even prefix on those beltways and similar route, leaving anything that is a spur to have an odd prefix. Illinois is one of those states.
I-55I-155: Connects I-55 to I-74, but never meets I-55 again.
I-255: Connects to I-55 at two ends (one in Missouri), and continues to meet I-270.
I-355: Connects I-55 to I-80 (south) and I-88 and I-290 (north), but only meets I-55 once.
I-70I-270: Connects to I-70 twice, once in Missouri.
I-72I-172: Connects to I-72 once, and spurs to a divided highway.
I-74I-474: Connects to I-74 at both ends.
I-80I-180: Spurs off I-80 to two lane roads.
I-280: Connects to I-80 at both ends (one in Iowa) and has a concurrency with I-74 just to meet I-80.
I-90I-190: Spurs off I-90 into O'Hare.
I-290: Connects to I-90 at both ends.
I-94I-294: Connects to I-94 at both ends and has a concurrency with I-80 just to meet I-94. Before I-90 and I-94 were switched, I-294 went into Indiana just to meet I-94.
I think that using even numbers in cases like I-880, with only one connection to its parent, makes it too difficult to create odd-starting 3dis. Here we go again with a state's even 3di's getting used up, when we haven't used half of the odd Iowa x80's. What if the Des Moines outer beltway becomes Interstate standard? I guess that will have to be an x35? There haven't been any even x29s used in Iowa...
Quote from: Mergingtraffic on October 14, 2019, 07:04:42 PM
From the FHWA it says this:
QuoteConnecting Interstate routes and full or partial circumferential beltways around or within urban areas carry a three-digit number. These routes are designated with the number of the main route and an even-numbered prefix. Supplemental radial and spur routes, connecting with the main route at one end, also carry a three-digit number, using the number of the main route with an odd-number prefix.
By looking at that statement I would say as long as both ends of a even-prefixed 3-digit interstate connect to another interstate, an even number is allowed.
To this day, many Rand McNally maps & atlases describe even 3-digit Interstates as:
First-digit even: Routes go through or around a cityThat said & based on the above-descriptions; I would be inclined to believe that even-prefixed 3dis that aren't complete/full beltways don't necessarily have to end at its parent 2di at both ends.
Quote from: kurumi on October 15, 2019, 12:55:38 AMThat guideline used to be honored more than it is now.
The likely reasoning for such is the result of some states
running out of available even prefixes; see the recent extended I-376 scenario in PA.
In retrospect, it might have been better to have swapped the odd/even-prefixed criteria for 3dis. Such was the reasoning for my starting this Fictional thread (https://www.aaroads.com/forum/index.php?topic=21718.0) a while back.
In Colorado, neither even-prefixed interstate loops or connects to its parent more than once.
I-225 connects to I-25 on the south and I-70 on the north, whereas I-270 connects to I-25 on the west and I-70 on the east.
The 470s (C-470 & E-470) serve as more of a loop (as they were originally intended to be designated as I-470) than the ones that actually have a blue and white shield.
Quote from: paulthemapguy on October 15, 2019, 10:16:44 AM
I think that using even numbers in cases like I-880, with only one connection to its parent, makes it too difficult to create odd-starting 3dis. Here we go again with a state's even 3di's getting used up, when we haven't used half of the odd Iowa x80's. What if the Des Moines outer beltway becomes Interstate standard? I guess that will have to be an x35? There haven't been any even x29s used in Iowa...
Personally, I thought it should be an I-x29, maybe I-829 to symbolize the connection between I-
80 and I-
29.
Michigan has a few odd 1st digit 3di's - 194, 196 and 375. All originally were spurs. I-196 was swapped with the westernmost portion of I-96 when what is now I-196 was not yet completed so a Detroit-Muskegon single route made more sense than an incomplete Detroit-Grand Rapids-Benton Harbor route.
Most even 1st digit routes in Michigan connect to their parent at both ends, with the exception of I-275 (although it was originally planned to) and I-696. Also the unmarked I-296, but that does connect I-96 and I-196 so it sort of meets the non-existent "connect at both ends" rule. But the exceptions connect to other Interstates at each end.
Quote from: Max Rockatansky on October 14, 2019, 11:14:20 PM
There is a tendency for even digit numbered routes to connect back to their parent but out here in California that trend is non-existent. A good example is the I-80 family of highways in California:
- I-280 doesn't even connect to it's parent but does by proxy to I-880 and I-680
- I-480 connected to it's parent but didn't loop back to it.
- Likewise I-680 and I-880 touch their parent route I-80 but definitely aren't loops.
Interestingly though I-405 and I-805 do loop to/from I-5 whereas none of the odd number child routes do. I-215 does loop to I-15 but that route was intended to be I-15E.
I-605 is the strangest of the bunch, intersecting I-5 basically mid-way through its route. It connects to Interstates on each end, but IMO acts more like two spurs (from I-5 north, I-605 north spurs to the San Gabriel Valley; from I-5 south, I-605 south spurs to coastal Orange County).
Quote from: PHLBOS on October 15, 2019, 10:21:29 AM
Quote from: Mergingtraffic on October 14, 2019, 07:04:42 PM
From the FHWA it says this:
QuoteConnecting Interstate routes and full or partial circumferential beltways around or within urban areas carry a three-digit number. These routes are designated with the number of the main route and an even-numbered prefix. Supplemental radial and spur routes, connecting with the main route at one end, also carry a three-digit number, using the number of the main route with an odd-number prefix.
By looking at that statement I would say as long as both ends of a even-prefixed 3-digit interstate connect to another interstate, an even number is allowed.
To this day, many Rand McNally maps & atlases describe even 3-digit Interstates as:
First-digit even: Routes go through or around a city
That said & based on the above-descriptions; I would be inclined to believe that even-prefixed 3dis that aren't complete/full beltways don't necessarily have to end at its parent 2di at both ends.
That's what I'm saying, even people in this thread think the "new" I-880 should be an odd 3di. I don't think it should as it connects two different interstates. I don't know where the Rand McNally thinking came from b/c the FHWA doesn't say that.
Quote from: Mergingtraffic on October 15, 2019, 03:19:02 PM
I don't know where the Rand McNally thinking came from b/c the FHWA doesn't say that.
Seriously. I mean, if that were true, then I-238 would...
Quote from: Mergingtraffic on October 15, 2019, 03:19:02 PMI don't know where the Rand McNally thinking came from b/c the FHWA doesn't say that.
Not sure of its origin; but such has been on many of its maps & atlases for decades.
Aside from Rand McNally not mentioning connections to Interstates at both ends (if not a full beltway), where does its definition differ from the FHWA's definition? There are examples of even 3dis going
through cities whereas its parent route bypasses it. I-295 going through Portland, ME vs. I-95/ME Turnpike bypassing Portland being one example. Note: Such existed
decades before the I-95/295 swap further north of Portland.
For comparison purposes, both definitions (FHWA & Rand McNally) are reposted below with
bold emphasis added:
Quote from: FHWAConnecting Interstate routes and full or partial circumferential beltways around or within urban areas carry a three-digit number. These routes are designated with the number of the main route and an even-numbered prefix. Supplemental radial and spur routes, connecting with the main route at one end, also carry a three-digit number, using the number of the main route with an odd-number prefix.
Quote from: Rand McNally description for even 3-digit Interstate on maps & atlases
First-digit even: Routes go through or around a city
Quote from: PHLBOS on October 15, 2019, 03:50:19 PM
Aside from Rand McNally not mentioning connections to Interstates at both ends
That's precisely it. RMN says an even-numbered 3di has to go through or around
a city. That is one possible reading of the FHWA guidance:
(Connecting Interstate routes and full or partial circumferential beltways) (around or within urban areas)
However, I don't think that's the correct interpretation of the guidance. I think instead, the guidance should be parsed thus:
(Connecting Interstate routes) (and full or partial circumferential beltways around or within urban areas)
That leaves open the possibility of a rural 3di. See I-135 in Kansas for a good example of that.
Radial/circumferential is my preference, but there are still a few problems, like I-355 in Illinois, which I feel is a correct odd number contrary to my preference.
I-880 is technically a spur that shortens the distance from Des Moines to Sioux City.
Even though it connects to another interstate, it isn't a belt route or a route through a city.
The first digit of the route number should be odd, whether the last two digits of the route number are 29 or 80.
Quote from: 1 on October 15, 2019, 04:03:18 PM
Radial/circumferential is my preference, but there are still a few problems, like I-355 in Illinois, which I feel is a correct odd number contrary to my preference.
At the risk of this being a Fictional Highways thread, let's do a couple of things here:
- Let's build the Illinois 53 extension through Lake County and connect it to US 12 at the Cheddar Curtain.
Let's extend I-355 south (Illiana Expressway or some mutation of it) and bend it east at least as far as I-65.
Let's call the entire route I-355.
So we'd now have another beltway around most of the Chicago area, but it would never cross a mainline Interstate twice.
Theoretically, working from the north, it could start at I-43 near Lake Geneva
It would cross I-90 at Schaumburg and I-88 near Downers Grove
It would cross I-55 and I-80 where it currently intersects them.
And it would cross I-57 and terminate at I-65
From none of these seven routes could you exit onto this highway and have a reasonable expectation that you would be reunited with the route you just left.
That's why it is (and would be) properly signed as an odd first digit 3di.
Quote from: Konza on October 15, 2019, 04:07:42 PM
I-880 is technically a spur that ... connects to another interstate ...
If it connects two Interstates, then it isn't a spur. That's not what "spur" means.
Okay, here we go with Indiana's three-digit interstates.
I-265: Currently connects I-64 and I-65 in the Louisville metro area and will be extended east to the Ohio River to form a 3/4 beltway around Louisville.
I-465: Beltway around Indianapolis.
I-865: Formerly a dogleg of Interstate 465, it was changed in 2002 to avoid the confusion. Connects I-65 in the northward direction (to/from Chicago) to I-465.
I-469: Partial beltway around the eastern side of Fort Wayne. Connects to I-69 on both ends.
I-275: Beltway around Cincinnati with I-275 serving three miles of Indiana which its parent route, I-75, does not go to.
No, we are not going to talk about I-164 which is now absorb into I-69.
Quote from: Great Lakes Roads on October 15, 2019, 04:23:22 PM
Okay, here we go with Indiana's three-digit interstates.
I-265: Currently connects I-64 and I-65 in the Louisville metro area and will be extended east to the Ohio River to form a 3/4 beltway around Louisville.
I-465: Beltway around Indianapolis.
I-865: Formerly a dogleg of Interstate 465, it was changed in 2002 to avoid the confusion. Connects I-65 in the northward direction (to/from Chicago) to I-465.
I-469: Partial beltway around the eastern side of Fort Wayne. Connects to I-69 on both ends.
I-275: Beltway around Cincinnati with I-275 serving three miles of Indiana which its parent route, I-75, does not go to.
No, we are not going to talk about I-164 which is now absorb into I-69.
AASHTO in the Spring 2019 session approved the Unified I-265 in IN/KY for the 3/4 bi-state Louisville Beltway. InDOT and KYTC haven't yet signed it, but it now is an approved designation
865 would have been a better 765, especially if a Western Extension to I-74 ever comes to pass imho, but probably too late on that
Quote from: Konza on October 15, 2019, 04:21:36 PM
From none of these seven routes could you exit onto this highway and have a reasonable expectation that you would be reunited with the route you just left.
That's why it is (and would be) properly signed as an odd first digit 3di.
So whats your take on the extended "candy cane" or "j hook" I-295 in Delaware/NJ/PA since the new I-95/PA Turnpike interchange and routing?
Traffic from either endpoint defaults onto I-95 South...there is no movement to (directly) utilize I-295 as an I-95 Bypass...used in combination with NJ I-195, yes.
Also is I-295 and I-95 in NJ the only place a Parent crosses its Child/Aux route with no Interchange? That would be the Logical place to put a full Interchange to utilize I-295 as a Bypass/Alternate to I-95...but it would also make shunpiking the southern NJ Turnpike much easier
Quote from: ilpt4u on October 15, 2019, 10:15:44 PM
Quote from: Konza on October 15, 2019, 04:21:36 PM
From none of these seven routes could you exit onto this highway and have a reasonable expectation that you would be reunited with the route you just left.
That's why it is (and would be) properly signed as an odd first digit 3di.
So whats your take on the extended "candy cane" or "j hook" I-295 in Delaware/NJ/PA since the new I-95/PA Turnpike interchange and routing?
Traffic from either endpoint defaults onto I-95 South...there is no movement to (directly) utilize I-295 as an I-95 Bypass...used in combination with NJ I-195, yes.
Also is I-295 and I-95 in NJ the only place a Parent crosses its Child/Aux route with no Interchange? That would be the Logical place to put a full Interchange to utilize I-295 as a Bypass/Alternate to I-95...but it would also make shunpiking the southern NJ Turnpike much easier
It certainly appears that I-295 was always intended to be an alternate route from Delaware to northern New Jersey. The connections at the north end are clumsy at best, and at least part of the route was built when I-95 was planned to follow a new terrain route north of Trenton. The northern section is a loop around Trenton and might benefit from a different route number but connects with the parent route at both ends, even if you have to use I-195 to make the connection.
When you take the ramp onto I-295, you have a reasonable expectation that you will be routed back to the parent route. I'd add that, in my I-355 example, if the beltway were to be extended east of I-65 to connect with I-80/90 in Indiana, I would support an even first digit 3di route number (I-X90?) for the section of the road between Schaumburg and that eastern connection.
Quote from: Konza on October 16, 2019, 12:00:13 PM
Quote from: ilpt4u on October 15, 2019, 10:15:44 PM
So whats your take on the extended "candy cane" or "j hook" I-295 in Delaware/NJ/PA since the new I-95/PA Turnpike interchange and routing?
Traffic from either endpoint defaults onto I-95 South...there is no movement to (directly) utilize I-295 as an I-95 Bypass...used in combination with NJ I-195, yes.
Also is I-295 and I-95 in NJ the only place a Parent crosses its Child/Aux route with no Interchange? That would be the Logical place to put a full Interchange to utilize I-295 as a Bypass/Alternate to I-95...but it would also make shunpiking the southern NJ Turnpike much easier.
It certainly appears that I-295 was always intended to be an alternate route from Delaware to northern New Jersey. The connections at the north end are clumsy at best, and at least part of the route was built when I-95 was planned to follow a new terrain route north of Trenton. The northern section is a loop around Trenton and might benefit from a different route number but connects with the parent route at both ends, even if you have to use I-195 to make the connection.
Regarding I-295 in the Delaware Valley, there's a couple things to keep in mind.
1. As you previously mentioned, the northern end of I-295 in NJ was originally where the Somerset Freeway (I-95 north of Trenton) would've been constructed.
2. There are still long-term plans to add the remaining
missing moves at the I-95/276/295 interchange in Bristol, PA. Once the I-295 to I-95 northbound and the I-95 southbound to I-295 ramps are built; one can theoretically go from I-295 northbound/westbound to I-95 northbound and/or go from I-95 southbound to I-295 eastbound/southbound... although such a move would not be desirable for long-distance traffic.
Quote from: Konza on October 16, 2019, 12:00:13 PM
When you take the ramp onto I-295, you have a reasonable expectation that you will be routed back to the parent route.
I-276 in PA says otherwise.
I still read it as, as long as an 3di meets an interstate at both ends it should be an even 3di.
CT has I-395 which connects I-95 at it southern end and I-290/I-90 at it's northern end in MA. I think I-290 should replace I-395. It's not a spur, it connects two different interstates.
Quote from: Mergingtraffic on October 17, 2019, 04:03:21 PM
I still read it as, as long as an 3di meets an interstate at both ends it should be an even 3di.
CT has I-395 which connects I-95 at it southern end and I-290/I-90 at it's northern end in MA. I think I-290 should replace I-395. It's not a spur, it connects two different interstates.
What would it be a loop around?
Quote from: Mergingtraffic on October 17, 2019, 04:03:21 PM
I still read it as, as long as an 3di meets an interstate at both ends it should be an even 3di.
CT has I-395 which connects I-95 at it southern end and I-290/I-90 at it's northern end in MA. I think I-290 should replace I-395. It's not a spur, it connects two different interstates.
It looked like it was going to be part of I-290 (in official statements and newspaper articles) until a few weeks before it was designated as I-395: https://www.kurumi.com/roads/ct/i290.html
Quote from: sprjus4 on October 14, 2019, 07:15:22 PM
Ideally, an even number should be used when the roadway is linking two interstate highways, whether it be the same interstate highway at either end (I.E. a beltway, bypass, etc.), or another interstate highway (I.E. a connector).
The 2nd half of this statement applies to I-220 in Jackson, MS. Connects I-20 on the west side of Jackson (Clinton, MS) to I-55 on the north side of Jackson (near Ridgeland).
Quote from: 1 on October 17, 2019, 10:23:53 PM
Quote from: Mergingtraffic on October 17, 2019, 04:03:21 PM
I still read it as, as long as an 3di meets an interstate at both ends it should be an even 3di.
CT has I-395 which connects I-95 at it southern end and I-290/I-90 at it's northern end in MA. I think I-290 should replace I-395. It's not a spur, it connects two different interstates.
What would it be a loop around?
The State of Rhode Island - although this would call for making it I-695 or I-895.
Or going further into fictional territory - make it a reroute of I-495, with existing I-495 south of existing I-290 becoming I-395.
This could easily be fixed by removing the prefix digit, and instead use a suffix digit indicating direction, with 5 and 0 being reserved for beltways, but not partial loops.
This would make the new I-880, I-802. I-680 in Omaha would become, in theory, I-809.
Quote from: Eth on October 14, 2019, 08:00:39 PM
Quote from: 1 on October 14, 2019, 07:35:14 PM
but it's also almost perfectly a straight line (which means odd).
Counterpoint: I-475 (GA) is nearly a straight line, but wouldn't make any sense at all with an odd first digit.
That highway connects to I-75 on both ends. And it is the route to take for long distance travel.
Quote from: TEG24601 on October 19, 2019, 12:36:50 PM
This would make the new I-880, I-802. I-680 in Omaha would become, in theory, I-809.
I have mused that this would be a reasonable convention for numbering auxillary routes of an interstate 100, 200, 300, etc.
There could be an I-104 in Florida that's a spur, but then there could be an I-104 in some other state that's a loop.
The rationale would be to free up unique numbers in the eastern third of the country for mainline interstates. It would have to be an O.G. part of the system though; you're not going to come in today and do it. But it makes for some fun fictional musings.
I pick angling interstate corridors that get out of the grid and slot in one of these 100 interstates. Like a combined I-81/I-78 corridor from eastern TN to NYC. Make it I-100. That frees 78 and either 81 or 83 because they become one corridor from Baltimore to Canada. Now I've got two numbers I can plug in elsewhere.
I think that I 196 is numbered the way it is because it was originally the spur route to Muskegon and I-96 was supposed to go to Benton Harbor so with the number swap it ended up where it is now
Quote from: TEG24601 on October 19, 2019, 12:36:50 PM
This could easily be fixed by removing the prefix digit, and instead use a suffix digit indicating direction, with 5 and 0 being reserved for beltways, but not partial loops.
This would make the new I-880, I-802. I-680 in Omaha would become, in theory, I-809.
In California, the x80s could follow the same convention and not conflict with state routes e.g. CA 180. But... I-5. Its auxiliary routes would be either "2-digit" routes (51, 52, etc.) or a weird leading zero convention (051, 052). And a bunch of state routes are in the way.
Quote from: kurumi on October 22, 2019, 02:19:07 AM
But... I-5. Its auxiliary routes would be either "2-digit" routes (51, 52, etc.) or a weird leading zero convention (051, 052). And a bunch of state routes are in the way.
You could go with 501, 502, etc., though I guess that has the minor drawback that I-8 and I-80 would have to share the same pool.
Hmmm, let's see how it is for I-95.
I-195 in ME connects to I-95 at one end
I-395 in ME connects to I-95 at one end
I-195 in NJ connects to I-295 at one end
I-395 in MD connects to I-95 at one end
I-795 in MD connects to I-695 at one end
I-395 in DC-VA connects to I-95/495 at one end
I-195 in VA connects to I-95 at one end
I-795 in NC connects to I-95 at one end
I-195 in FL connects to I-95 at one end
I-395 in FL connects to I-95 at one end
I-295 in ME connects to I-95 at both ends
I-495 in ME connects I-95 and I-295
I-295 in MA and RI connects to I-95 at both ends
I-495 in MA connects to I-95 at both ends
I-695 in NY connects I-95 and I-295
I-295 in NJ, PA, and DE connects to I-95 at both ends (even before the golden spike)
I-495 in DE connects to I-95 at both ends
I-295 in MD and VA connects I-95/495 and I-695
I-495 in MD, DC, and VA is a beltway
I-695 in MD is a beltway
I-895 in MD connects to I-95 at both ends
I-695 in DC connects I-395 and I-295
I-295 in VA connects I-95 and I-64
I-295 in FL is a beltway
I-195 in MA and RI connects I-95 and I-495
I-395 in CT and MA connects I-95 and I-90/I-290
I-195 in MD connects to I-95 in the middle, but neither of its termini are at interstates
I-595 in MD connects to I-95/495 in the middle, but neither of its termini are at interstates
I-595 in FL connects to I-95 in the middle, but neither of its termini are at interstates
I-295 in NY connects to I-95 at one end (though not if it were built as planned)
I-495 in NY connects to I-295 in the middle, but neither of its termini are at interstates
Quote from: TheGrassGuy on November 26, 2019, 02:38:28 PM
I-595 in MD connects to I-95/495 in the middle, but neither of its termini are at interstates
MD I-595 (unposted) follows US-50 and connects I-495/I-95 to MD-70.
It doesn't go west of I-495/I-95.
Quote from: Beltway on November 26, 2019, 08:49:32 PM
Quote from: TheGrassGuy on November 26, 2019, 02:38:28 PM
I-595 in MD connects to I-95/495 in the middle, but neither of its termini are at interstates
MD I-595 (unposted) follows US-50 and connects I-495/I-95 to MD-70.
It doesn't go west of I-495/I-95.
Source, please? I know that the western terminus of the John Hanson Hwy is at the Baltimore-Washington Pkwy, but that's not an interstate.
Quote from: TheGrassGuy on November 26, 2019, 08:52:30 PM
Quote from: Beltway on November 26, 2019, 08:49:32 PM
Quote from: TheGrassGuy on November 26, 2019, 02:38:28 PM
I-595 in MD connects to I-95/495 in the middle, but neither of its termini are at interstates
MD I-595 (unposted) follows US-50 and connects I-495/I-95 to MD-70.
It doesn't go west of I-495/I-95.
Source, please? I know that the western terminus of the John Hanson Hwy is at the Baltimore-Washington Pkwy, but that's not an interstate.
I-595 in Maryland is the longest unsigned route within the Interstate Highway System. Aligned entirely along U.S. 50 (John Hanson Highway) and partially along U.S. 301, the I-595 designation applies to the freeway between I-95/495 (Capital Beltway) and Maryland 70 at Annapolis.
https://www.interstate-guide.com/i-595-md/
Interstate 595 lines 19.97 miles of the U.S. 50 freeway (John Hanson Highway) between the Capital Beltway (Interstates 95 & 495) and the interchange with Maryland 70 (Rowe Boulevard) at Annapolis. This stretch of U.S. 50 was designated as an Interstate in 1989.
https://www.aaroads.com/guides/i-595-md/
The segment of US-50 from I-495 to Annapolis was approved for Interstate construction as I-68.
US-50 from I-495/I-95 to MD-70 was reconstructed to six-lane Interstate standards from 1990 to 1995. All the interchanges were reconstructed also, including the new full semi-directional interchange between US-50 and the Capital Beltway (I-95/I-495).
When the National Freeway in Western Maryland was completed in 1991, it was given the I-68 designation, and US-50 (I-495 Capital Beltway to MD-70 Roscoe Rowe Blvd.) was authorized to receive the I-595 designation, an Interstate spur from I-95 to Annapolis.
http://www.roadstothefuture.com/I595_MD.html
The US-50 freeway west of the Beltway has not had an Interstate designation.
Quote from: TheGrassGuy on November 26, 2019, 02:38:28 PMI-495 in MA connects to I-95 at both ends
Prior to the southern extension opening circa 1982, such was true. Since then, the southern end of I-495 in MA is at I-195/MA 25.
Quote from: ilpt4u on October 15, 2019, 10:00:06 PM
865 would have been a better 765, especially if a Western Extension to I-74 ever comes to pass imho, but probably too late on that
I proposed that once on a Fictional Highways thread and most of the responses said it would be redundant.
Quote from: 1 on October 14, 2019, 07:35:14 PM
It could go either way for 880. It's circumferential, not radial, with regard to Omaha (which means even), but it's also almost perfectly a straight line (which means odd).
Quote from: Max Rockatansky on October 14, 2019, 11:14:20 PM
There is a tendency for even digit numbered routes to connect back to their parent but out here in California that trend is non-existent. A good example is the I-80 family of highways in California:
- I-280 doesn't even connect to it's parent but does by proxy to I-880 and I-680
- I-480 connected to it's parent but didn't loop back to it.
- Likewise I-680 and I-880 touch their parent route I-80 but definitely aren't loops.
Interestingly though I-405 and I-805 do loop to/from I-5 whereas none of the odd number child routes do. I-215 does loop to I-15 but that route was intended to be I-15E.
And I-215 goes way out of its way in doing so, curving easterly on CA 60. If you want a more straightforward route back to I-15 out of Riverside, you'd use 91 to meet 15 in Corona.
As for I-605, if it didn't connect to the 405 on the south to return to I-5, that would need to be 705 or 305.
Hell, I-105 doesn't connect to its parent route at all except by using I-605 north to I-5. It was originally meant to but Caltrans figured the 5 couldn't handle it, not to mention the prevalent NIMBY's of the time revolted against it.