Beyond the obvious loop vs. spur (even vs. odd), what categories of 3di (3-digit Interstate) can be said to exist? Start with odd and even as the two primary divisions, then subdivide. Some possible examples:
Bypass (I-481)
Beltway (I-285)
Loop from a parent into a nearby city (I-490 NY)
Loop within a city, alternate to the parent (I-405 CA)
Loop forming one side of a circumferential figure (I-444)
Spur towards a city (I-176)
Spur away from a city (I-990)
Double spur (I-540, at least formerly)
Downtown spur (I-375)
Long-distance branch route (I-135)
Wye (I-505)
And so on!
The "exit ramps" :bigass:
(I-189 in VT, I-175 & I-375 in FL, etc.)
orphan (I-278)
Jesus (I-238)
Quote from: NE2 on January 08, 2015, 01:55:06 AM
orphan (I-278)
Jesus (I-238)
I disagree. Jesus had Mary (which should be at least half of I-38, therefore... oh hell, it's I-19!)
Quote from: adventurernumber1 on January 08, 2015, 01:13:31 AM
The "exit ramps" :bigass:
(I-189 in VT, I-175 & I-375 in FL, etc.)
I-381 fits very nicely into this category.
I-180 in Wyoming and I-587 in New York fit into the category "how the hell did they get interstate funding?"
I-635 (KC), a bypass from one interstate to a different interstate.
I-635 (Dallas), a spur plus a bypass from one interstate to a different interstate and that bypass is also half of a 3/4 beltway.
I-345 (Dallas), a spur adjacent to downtown continuing as a non-Interstate freeway.
In CT
I-291 and I-691: Connector routes between 2 2di's that could have been much more.
I-384: A remnant stub of a 2di killed by NIMBYs and environmentalists.
I-395: A long distance 3di through the middle of nowhere which changes numbers suddenly when it hits another 2di.
I-684:, A downgrading of a rerouted 2di.
Add I-395 in MD to the glorified exit ramp list.
I-170 MD and I-895 NY: WTF? 3dis
Incest 3DI: I-495/DC Beltway When a 3di and 2Di that were meant to be seperate ended up becoming one and the same.
Are full beltways and half beltways considered different?
Quote from: SteveG1988 on January 08, 2015, 07:37:33 AM
Incest 3DI: I-495/DC Beltway When a 3di and 2Di that were meant to be seperate ended up becoming one and the same.
I can think of I-87/287 in New York, I-80/580 in San Francisco, and the aforementioned. Are there any other examples?
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
Quote from: froggie on January 08, 2015, 08:49:26 AM
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
I'm too lazy to look up how long it lasted (or even if they were even signed as such) but I do know that New York submitted two different numbers to AASHO for each of the two independent portions.
Quote from: froggie on January 08, 2015, 08:49:26 AM
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
Wasn't 87 originally supposed to cross over and come down on the east side of the Hudson?
I-210 (CA)
I-110 (CA)
3-dis that continue as same numbered state routes. I'd say 238, but I think that's better in the "orphan" category.
Quote from: Kacie Jane on January 08, 2015, 09:40:02 AM
Quote from: froggie on January 08, 2015, 08:49:26 AM
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
I'm too lazy to look up how long it lasted (or even if they were even signed as such) but I do know that New York submitted two different numbers to AASHO for each of the two independent portions.
The Cross-Westchester Expressway was originally numbered I-487. New York for whatever reason wanted it to be a single route with the 287 in New Jersey, and it made sense to combine them over I-87 into one route.
Quote from: Pete from Boston on January 08, 2015, 09:45:00 AMWasn't 87 originally supposed to cross over and come down on the east side of the Hudson?
I-684 was originally planned to be I-87.
I'd heard this, that I-87 was intended on the east side of the Hudson farther north. Curiously, though, this is not reflected in the Yellow Book (http://www.ajfroggie.com/roads/yellowbook/newyorkcity.jpg). It was afterwards that I-87 was routed along today's I-684, then eventually shifted back.
I can think of a few Chicagoland examples:
I-190: Spur into the main airport (O'Hare)
I-290: North/west bypass
I-294: Half-beltway around city
I-355: Two-way spur off I-55
Quote from: ajlynch91 on January 08, 2015, 10:48:53 AM
Quote from: Kacie Jane on January 08, 2015, 09:40:02 AM
Quote from: froggie on January 08, 2015, 08:49:26 AM
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
I'm too lazy to look up how long it lasted (or even if they were even signed as such) but I do know that New York submitted two different numbers to AASHO for each of the two independent portions.
The Cross-Westchester Expressway was originally numbered I-487. New York for whatever reason wanted it to be a single route with the 287 in New Jersey, and it made sense to combine them over I-87 into one route.
I think it's the reverse: NY wanted I-487 for the Cross-Westchester and I-287 for NJ, but the FHWA or AASHTO wanted them combined. This is due to the thought difference in what I-287 is: to those of us from upstate NY, it is two separate entities not at all related, a bypass of the Cross-Bronx, and a bypass of the Turnpike. To everyone else, however, it's a beltway around NYC.
Per Kurumi, AASHO approved separate 287 (west of Elmsford) and 487 (east of White Plains) in 1958. The two were combined in 1961.
Quote from: ajlynch91 on January 08, 2015, 05:53:49 AM
Quote from: adventurernumber1 on January 08, 2015, 01:13:31 AM
The "exit ramps" :bigass:
(I-189 in VT, I-175 & I-375 in FL, etc.)
I-381 fits very nicely into this category.
OK, what do we call this type? "Connector spur"? Is there any distinction between the downtown type (I-395 MD) and the outskirts type (I-115)?
Quote from: dfwmapper on January 08, 2015, 06:42:46 AM
I-635 (KC), a bypass from one interstate to a different interstate.
I-635 (Dallas), a spur plus a bypass from one interstate to a different interstate and that bypass is also half of a 3/4 beltway.
I-345 (Dallas), a spur adjacent to downtown continuing as a non-Interstate freeway.
I do think it's worth considering parentage in the classification. For example, a 3di off its parent is the default, a 3di off another 3di would be "second-order" or "sub-level", a 3di from a non-parent would be "unaffiliated", and so on. And of course there are hybrid cases.
Quote from: jp the roadgeek on January 08, 2015, 07:21:48 AM
In CT
I-291 and I-691: Connector routes between 2 2di's that could have been much more.
I-384: A remnant stub of a 2di killed by NIMBYs and environmentalists.
I-395: A long distance 3di through the middle of nowhere which changes numbers suddenly when it hits another 2di.
I-684:, A downgrading of a rerouted 2di.
Interesting histories aside, how can we categorize these according to their current state? I-691 seems a familiar type, a sort of branch/bypass; perhaps it's a "wye" like I-505?
I-291 is a bypass, but a certain kind that cuts a corner of a right-angle movement, rather than a half-loop that bypasses straight-thru traffic.
I-384 definitely looks like a "spur away from a city".
I-395 present an important case: a long-distance, intercity "spur", like I-380 IA, I-135, or I-476 PA (how do we reconcile the evenness of the latter?). I-395 does change numbers just shy of Worcester, but I think we can consider it as approaching that city.
I-684 is kind of another candidate for this category.
Quote from: 1 on January 08, 2015, 07:46:20 AM
Are full beltways and half beltways considered different?
Yes, I think definitely so. What I also wonder is, are half-beltways and bypasses different? Can we find 3dis that are demonstrably one or the other, perhaps I-494/I-694, or I-481, or I-405 CA...?
Quote from: OCGuy81 on January 08, 2015, 10:15:43 AM
I-210 (CA)
I-110 (CA)
3-dis that continue as same numbered state routes. I'd say 238, but I think that's better in the "orphan" category.
I-210 seems like I-405, except that it's a right-angle bypass (albeit a very long one) instead of a straight-thru one (if I-405 is indeed a bypass at all). And both routes are definitely also "loops through a city", passing through interior areas of the city, but not the central city. I-278 is also this way (but of course, it's "unaffiliated").
Quote from: Henry on January 08, 2015, 12:42:49 PM
I can think of a few Chicagoland examples:
I-190: Spur into the main airport (O'Hare)
I-290: North/west bypass
I-294: Half-beltway around city
I-355: Two-way spur off I-55
Airport spur is an important addition; there are definitely a few of those (I-380 CA, I-105 CA–but that's also a crosstown sort of route, more than simply an airport spur).
I-355 is interesting: it sure looks like a bypass, but the first digit tells us it's a spur, so...?
Quote from: empirestate on January 08, 2015, 01:03:44 PMI-395 present an important case: a long-distance, intercity "spur", like I-380 IA, I-135, or I-476 PA (how do we reconcile the evenness of the latter?). I-395 does change numbers just shy of Worcester, but I think we can consider it as approaching that city.
I-395 was originally CT/MA 52. The redesignation to I-395 came about as a result of (mostly CT) trading in some unbuilt Interstate miles. Since this was largely CT's doing; the option of extending I-290 south into CT and to I-95 was probably not considered an option.
Due to the highway going into MA; 395 was chosen because 195 was already being used in MA (& RI).
As previously mentioned, the reasoning behind PA 9 becoming an extension of I-476, as opposed to another I-x76 or even a I-x81, was rather obvious given that the Blue Route ended at the Turnpike (I-276)/NE Extension interchange.
QuoteLoop from a parent into a nearby city (I-490 NY)
I would call that a business loop. I-490 is similar to the I-95 business route for Fayetteville NC. The difference being the latter is not a freeway for it's entire length. But they serve the same purpose. The main interstate does not directly serve the city. So the business loop serves the city for the main route.
Oregon and Washington:
I-105 - Spur into a city
I-205 - Loop within a city/alternate to parent (and formally planned to be half of a circumferential)
I-305 (canceled) - Spur into a city
I-405 (both) - Loop within a city/alternate to parent
I-505 (canceled) - Spur away from a city
"I-605" - Loop around a city
I-705 - Spur into a city
I-535: Spur into a city
I-394: Spur into a city
I-694: Bypass/alternate to parent
I-494 is hard for me to peg because it doesn't really neatly fit into any of the categories. It goes out of the way too much to be either a bypass or alternate to I-94, and also serves a number of major MSP suburbs on its own accord. It's basically its own animal with an x94 attached to it.
494/694 is obviously a beltway.
Quote from: NE2 on January 08, 2015, 05:53:25 PM
494/694 is obviously a beltway.
Yes, but as separate routes they serve different functions - and MNDot no longer advertises 494 as part of the bypass route.
Military spurs: I-564 and I-781
I-495 (MA):
Half beltway (not a bypass of I-95 though)
But it also serves as a Lowell-Lawrence-Haverhill connector (and is also part of the way from most of the United States to Maine).
A rare example of a 3di over 100 miles (and turning it into a 2di makes no sense).
Quote from: TheHighwayMan394 on January 08, 2015, 06:13:19 PM
Quote from: NE2 on January 08, 2015, 05:53:25 PM
494/694 is obviously a beltway.
Yes, but as separate routes they serve different functions - and MNDot no longer advertises 494 as part of the bypass route.
A beltway is not always a good bypass. See I-275 around Cinci.
Quote from: BrianP on January 08, 2015, 03:23:46 PM
QuoteLoop from a parent into a nearby city (I-490 NY)
I would call that a business loop. I-490 is similar to the I-95 business route for Fayetteville NC. The difference being the latter is not a freeway for it's entire length. But they serve the same purpose. The main interstate does not directly serve the city. So the business loop serves the city for the main route.
The name that was occurring to me was "remote city loop", to connote that it serves a city that the parent route avoids, but "business loop" does suit another aspect of its function.
Quote from: Bickendan on January 08, 2015, 05:32:56 PM
Oregon and Washington:
I-205 - Loop within a city/alternate to parent (and formally planned to be half of a circumferential)
I-405 (both) - Loop within a city/alternate to parent
I-405 OR seems to me quite a different animal from I-405 WA or I-205, because of its path through only the central city rather than traversing much of the metro area.
Quote from: TheHighwayMan394 on January 08, 2015, 05:41:14 PM
I-535: Spur into a city
I-394: Spur into a city
I-694: Bypass/alternate to parent
I-494 is hard for me to peg because it doesn't really neatly fit into any of the categories. It goes out of the way too much to be either a bypass or alternate to I-94, and also serves a number of major MSP suburbs on its own accord. It's basically its own animal with an x94 attached to it.
I-535, a spur into Superior, rather than a spur away from Duluth? It does sort of have a dual function; another such example would be I-190 NY, which is both a spur into Buffalo and a longer-distance spur to Niagara Falls.
For I-694, is there a distinction to be made between "bypass" and "alternate"? The latter seems to suggest more equivalence between two options, while a "bypass" seems like a route that's clearly less local than the through route.
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Good addition. Perhaps these, along with airport spurs and some others (I-180 IL) could be subsets of a category called "facility spurs"?
Quote from: admtrap on January 08, 2015, 04:31:08 AM
Quote from: NE2 on January 08, 2015, 01:55:06 AM
orphan (I-278)
Jesus (I-238)
I disagree. Jesus had Mary (which should be at least half of I-38, therefore... oh hell, it's I-19!)
Is I-238 an 'Adam' then?
Quote from: english si on January 08, 2015, 06:53:11 PM
Quote from: admtrap on January 08, 2015, 04:31:08 AM
Quote from: NE2 on January 08, 2015, 01:55:06 AM
orphan (I-278)
Jesus (I-238)
I disagree. Jesus had Mary (which should be at least half of I-38, therefore... oh hell, it's I-19!)
Is I-238 an 'Adam' then?
More like Frankenstein's Monster.
Quote from: empirestate on January 08, 2015, 01:03:44 PM
Quote from: ajlynch91 on January 08, 2015, 05:53:49 AM
Quote from: adventurernumber1 on January 08, 2015, 01:13:31 AM
The "exit ramps" :bigass:
Quote from: Henry on January 08, 2015, 12:42:49 PM
I can think of a few Chicagoland examples:
I-190: Spur into the main airport (O'Hare)
I-290: North/west bypass
I-294: Half-beltway around city
I-355: Two-way spur off I-55
Airport spur is an important addition; there are definitely a few of those (I-380 CA, I-105 CA–but that's also a crosstown sort of route, more than simply an airport spur).
I-355 is interesting: it sure looks like a bypass, but the first digit tells us it's a spur, so...?
I-355 is becoming more of a suburban spur. Still would consider it a bypass (bypass of bypass maybe??)
Quote from: ajlynch91 on January 08, 2015, 08:20:32 AM
Quote from: SteveG1988 on January 08, 2015, 07:37:33 AM
Incest 3DI: I-495/DC Beltway When a 3di and 2Di that were meant to be seperate ended up becoming one and the same.
I can think of I-87/287 in New York, I-80/580 in San Francisco, and the aforementioned. Are there any other examples?
I-94/694 in Minnesota
There's also the spur to the middle of nowhere, of which there is I-180 (IL), I-172 and I-155 (MO-TN), possibly others I missed.
We could always go with the unsigned
I-305 (CA)
I-345 (TX)
I-444 (OK)
And so on.
I'd peg I-394 more as a spur away from a city than into (though the portion running east from I-94 qualifies it).
I-495 in Maine, anyone? Is there a "You shoulda seen me, kid–I was somebody!" category?
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Numbers don't reflect it, but you could consider I-H2 and I-H3 to fall in this category
Quote from: OCGuy81 on January 08, 2015, 10:15:43 AM
I-210 (CA)
I-110 (CA)
3-dis that continue as same numbered state routes. I'd say 238, but I think that's better in the "orphan" category.
I-759 (AL)
I-520, Augusta, GA: odd first digit for a bypass loop? :hmmm:
Quote from: cjk374 on January 10, 2015, 01:33:25 PM
I-520, Augusta, GA: odd first digit for a bypass loop? :hmmm:
It was originally a spur before it was extended on the east side to reconnect.
Quote from: Big John on January 10, 2015, 02:11:11 PM
Quote from: cjk374 on January 10, 2015, 01:33:25 PM
I-520, Augusta, GA: odd first digit for a bypass loop? :hmmm:
It was originally a spur before it was extended on the east side to reconnect.
Yeah, that's a wrench in the works. Then again, look as I-526, which is a very similar half-loop bypass, except that the parent bisects it instead of forming the base of the loop. Can we say that whatever "type" I-526 is, I-520 is the same type?
iPhone
Quote from: empirestate on January 10, 2015, 03:12:43 PM
Yeah, that's a wrench in the works. Then again, look as I-526, which is a very similar half-loop bypass, except that the parent bisects it instead of forming the base of the loop. Can we say that whatever "type" I-526 is, I-520 is the same type?
Would I-140 in Wilmington also fit this as well?
I-495 on Long Island acts as its own independent interstate. In fact for Long Islanders it is known locally as the LIE, which serves as the region's backbone freeway.
Quote from: TheStranger on January 10, 2015, 04:38:27 PM
Quote from: empirestate on January 10, 2015, 03:12:43 PM
Yeah, that's a wrench in the works. Then again, look as I-526, which is a very similar half-loop bypass, except that the parent bisects it instead of forming the base of the loop. Can we say that whatever "type" I-526 is, I-520 is the same type?
Would I-140 in Wilmington also fit this as well?
Maybe, depending on how much is actually built and designated yet. On closer inspection, right now it looks more like a right-angle cutoff between the "east" and "north" quadrants than a full half-loop (and then another separate cutoff on the west side).
iPhone
Should I-180 IL get a "just kind of there" category? Technically it's a spur to a city, but the "city" in question has 750 people, and the steel plant it was meant to serve closed. Are there any other spurs like that which don't have a real purpose anymore?
What would I-380 south of SF be considered?
It's only a couple miles long and was basically added because living along 280 meant it was pretty terrible to get to the SFO airport on US-101 via back roads.
Quote from: TheCatalyst31 on January 10, 2015, 07:29:25 PM
Should I-180 IL get a "just kind of there" category? Technically it's a spur to a city, but the "city" in question has 750 people, and the steel plant it was meant to serve closed.
How about "pork spur"? I am sure there are plenty of other steel plants in the US that could have used an interstate spur.
I-794 - "Bridge"
I-894 - "Redundant" (true definition: bypass)
Quote from: relaxok on January 10, 2015, 08:39:49 PM
What would I-380 south of SF be considered?
It's only a couple miles long and was basically added because living along 280 meant it was pretty terrible to get to the SFO airport on US-101 via back roads.
Well, my answer for it was "airport spur" or the broader category "facility spur".
Quote from: TheCatalyst31 on January 10, 2015, 07:29:25 PM
Should I-180 IL get a "just kind of there" category? Technically it's a spur to a city, but the "city" in question has 750 people, and the steel plant it was meant to serve closed. Are there any other spurs like that which don't have a real purpose anymore?
I-69 in MS.
Quote from: empirestate on January 10, 2015, 09:52:05 PM
Quote from: relaxok on January 10, 2015, 08:39:49 PM
What would I-380 south of SF be considered?
It's only a couple miles long and was basically added because living along 280 meant it was pretty terrible to get to the SFO airport on US-101 via back roads.
Well, my answer for it was "airport spur" or the broader category "facility spur".
380 was intended to be longer (extending west of I-280), but it does serve a purpose in providing part of the most direct route from the Golden Gate Bridge to SFO via CA 1, I-280, and I-380. Despite its through numbering, US 101 is not the faster route between these two points (most of the time).
Quote from: relaxok on January 10, 2015, 08:39:49 PM
What would I-380 south of SF be considered?
It's only a couple miles long and was basically added because living along 280 meant it was pretty terrible to get to the SFO airport on US-101 via back roads.
I thought of 380 as the way to get from 101 on the peninsula to the Golden Gate Bridge via 19th Ave. and Park Presidio Blvd. in S.F., much faster than following 101 up Van Ness.
Those routes are actually usually comparable in time (I take both often).
Quote from: relaxok on January 11, 2015, 01:08:28 AM
Those routes are actually usually comparable in time (I take both often).
Okay, I'll take your word for it. CA 1 is prettier and less annoying though.
Well intentioned shortcut that scares drivers away with the word "TOLL:" I-185 (SC)
Coastal area traffic funnel: I-526 (SC), I-516 (GA)
Quote from: cl94 on January 09, 2015, 03:01:36 PM
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Numbers don't reflect it, but you could consider I-H2 and I-H3 to fall in this category
Especially I-H3, which shares a distinction with I-781 as ending directly at the entrance to a military facility (both I-H2 and I-564 end near such facilities, but directly at the gate).
Quote from: froggie on January 11, 2015, 03:02:15 PM
Quote from: cl94 on January 09, 2015, 03:01:36 PM
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Numbers don't reflect it, but you could consider I-H2 and I-H3 to fall in this category
Especially I-H3, which shares a distinction with I-781 as ending directly at the entrance to a military facility (both I-H2 and I-564 end near such facilities, but directly at the gate).
And I-185 in GA should go into this category as well.
Quote from: Zzonkmiles on January 11, 2015, 08:01:30 AM
Coastal area traffic funnel: I-526 (SC), I-516 (GA)
It would be more accurate to call these traffic deltas as they divert a large amount of beach-bound traffic around the coastal city. I-140 and possibly I-664 would also fit into this category.
Quote from: Henry on January 11, 2015, 03:54:21 PM
Quote from: froggie on January 11, 2015, 03:02:15 PM
Quote from: cl94 on January 09, 2015, 03:01:36 PM
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Numbers don't reflect it, but you could consider I-H2 and I-H3 to fall in this category
Especially I-H3, which shares a distinction with I-781 as ending directly at the entrance to a military facility (both I-H2 and I-564 end near such facilities, but directly at the gate).
And I-185 in GA should go into this category as well.
The freeway extends into Fort Benning, but I-185 itself doesn't...it ends at the 27/280 interchange. Whereas 781 and H3 end almost literally at the base gate.
I-195 in NJ: Double spur, leading to a "beltway" in one direction (I-295) and a toll road (GSP) in the other
I-370 in MD: Formerly a glorified exit ramp off of a 2di, to a subway station. Now a seamless lead-in to a toll road (MD-200/ICC)
I-470 in OH/WV: Bypass of a tunnel (not to be confused with I-895 in MD, which only takes you through a different tunnel)
In the Atlanta, GA area:
-- I-575: Spur leading from outside of a city to way outside of a city?
-- I-675: Shortcut to a beltway?
Quote from: vdeane on January 08, 2015, 12:52:35 PM
Quote from: ajlynch91 on January 08, 2015, 10:48:53 AM
Quote from: Kacie Jane on January 08, 2015, 09:40:02 AM
Quote from: froggie on January 08, 2015, 08:49:26 AM
I don't think 87/287 were meant to be separate, so probably shouldn't count that. I'd also use a more appropriate term than "incest". Perhaps "conjoined"?
I'm too lazy to look up how long it lasted (or even if they were even signed as such) but I do know that New York submitted two different numbers to AASHO for each of the two independent portions.
The Cross-Westchester Expressway was originally numbered I-487. New York for whatever reason wanted it to be a single route with the 287 in New Jersey, and it made sense to combine them over I-87 into one route.
I think it's the reverse: NY wanted I-487 for the Cross-Westchester and I-287 for NJ, but the FHWA or AASHTO wanted them combined. This is due to the thought difference in what I-287 is: to those of us from upstate NY, it is two separate entities not at all related, a bypass of the Cross-Bronx, and a bypass of the Turnpike. To everyone else, however, it's a beltway around NYC.
It's a bypass of the Cross-Bronx, and a bypass of the Turnpike, and a bypass of 80, and a bypass of 78...
A beltway is a connected continuum of bypasses. Sometimes you have to turn off the states.
Quote from: Thing 342 on January 11, 2015, 04:00:07 PM
Quote from: Zzonkmiles on January 11, 2015, 08:01:30 AM
Coastal area traffic funnel: I-526 (SC), I-516 (GA)
It would be more accurate to call these traffic deltas as they divert a large amount of beach-bound traffic around the coastal city. I-140 and possibly I-664 would also fit into this category.
Fair point. I was thinking more of the opposite-direction traffic flow with these 3dis collecting (funneling) traffic from the coastal suburbs onto the main 2di (in these cases, I-26 and I-16). You are talking about traffic going from the 2di to the 3di, which is entirely valid. :)
Quote from: froggie on January 11, 2015, 06:04:57 PM
Quote from: Henry on January 11, 2015, 03:54:21 PM
Quote from: froggie on January 11, 2015, 03:02:15 PM
Quote from: cl94 on January 09, 2015, 03:01:36 PM
Quote from: Takumi on January 08, 2015, 06:17:51 PM
Military spurs: I-564 and I-781
Numbers don't reflect it, but you could consider I-H2 and I-H3 to fall in this category
Especially I-H3, which shares a distinction with I-781 as ending directly at the entrance to a military facility (both I-H2 and I-564 end near such facilities, but directly at the gate).
And I-185 in GA should go into this category as well.
The freeway extends into Fort Benning, but I-185 itself doesn't...it ends at the 27/280 interchange. Whereas 781 and H3 end almost literally at the base gate.
This is what LaDOTD has planned for I-220' eastern end. They want to build the interstate onto Barksdale AFB property (which is the reason why I-220 will never be a full loop around Shreveport/ Bossier City) and build a new gate onto the base.
WV's only 3di is a bypass of Wheeling (I-470).
Quote from: lepidopteran on January 11, 2015, 06:44:30 PM
I-195 in NJ: Double spur, leading to a "beltway" in one direction (I-295) and a toll road (GSP) in the other
I-195 was designed as a spur off of I-295. The Turnpike being redesignated at I-95 is just coincidence.
Quote from: kkt on January 11, 2015, 01:18:56 AM
Quote from: relaxok on January 11, 2015, 01:08:28 AM
Those routes are actually usually comparable in time (I take both often).
Okay, I'll take your word for it. CA 1 is prettier and less annoying though.
If you're referring to the Junipero Serra Freeway/19th Avenue/Park Presidio Boulevard section of Route 1 (between 280 and the Presidio)...other than Golden Gate Park, I don't think there's much scenic on that side, while US 101 passes right by City Hall and provides Presidio access that 1 doesn't.
(As Andy noted, 380-280-1 is generally the shorter route...though traffic on 19th CAN be as much of a factor as traffic along Van Ness/Lombard. The latter though contains a lot of outbound/inbound commuters heading into downtown.)
The late I-181 in Tennessee was a double spur.
Anyone mentioned the international spurs yet? (i.e I-190 in NY, I-110 in Texas, I-375 in MI (ends near the Detroit-Windsor Tunnel), and Future I-905 in CA.
Quote from: cwf1701 on January 13, 2015, 12:57:54 AM
Anyone mentioned the international spurs yet? (i.e I-190 in NY, I-110 in Texas, I-375 in MI (ends near the Detroit-Windsor Tunnel), and Future I-905 in CA.
That sort of occurred to me, but I wasn't sure whether it should constitute its own category, or just be a subset of other types (downtown spur, facility spur, etc.).