3DI Interstates with an even first digit--should they be considered bypasses?

[msubulldog]

285 around Atlanta and 495 around Washington DC are the most obvious examples. But why aren't other such "loops"/"beltways"/"perimeters" like 410 in San Antonio, 610 in Houston, and 635 in Dallas considered bypasses?

[Flint1979]

285 around Atlanta and 495 around Washington DC are the most obvious examples. But why aren't other such "loops"/"beltways"/"perimeters" like 410 in San Antonio, 610 in Houston, and 635 in Dallas considered bypasses?

They are considered beltways.

[txstateends]

One I would consider more of a bypass would be I-610 in New Orleans.

[KEVIN_224]

[Photo Credit: Doug Kern]



A fried of mine snapped this picture near the westbound beginning of I-10 in Jacksonville. He said there was no "BEGIN" sign. I've never been in this part of Florida, but I DO know that the I-295 beltway wasn't finished all that long ago.

[Henry]

Since an even first digit denotes a route through or around a city, then I guess that the route can be considered a bypass, even if it does not completely avoid the city it serves. A prime example is I-290, which starts in Chicago, but ends in the western suburbs, and vice versa.

[webny99]

I-490 in Rochester sure as heck isn't a bypass. It goes right through downtown.

I'm not of the belief that even-numbered 2dis should have to be signed as bypasses. It's more important that they fit more generally, into the category of having two junctions with the 2di of which they originated from. Similarly, it's not important that odd numbers are true spurs, just that they only have one junction with their associated 2di.

Take I-290 in Buffalo, for example. It's hard to say if it should be an even or an odd number, since it facilitates through traffic but doesn't connect to I-90 on both ends. Beltways (or other bypasses) should always be even numbers; spurs should always be odd numbers. But some 3dis don't fit neatly into either category.

[US71]

Per Wikipedia

An odd hundreds digit means the route connects at only one end to the rest of the interstate system, known as a "spur route". An even hundreds digit means the route connects at both ends, which could be a loop route (which has two termini) or a radial route (known also as a beltway, beltline, or circumferential route).

[webny99]

Per Wikipedia

An odd hundreds digit means the route connects at only one end to the rest of the interstate system, known as a "spur route". An even hundreds digit means the route connects at both ends, which could be a loop route (which has two termini) or a radial route (known also as a beltway, beltline, or circumferential route).

I'm not of the belief that even-numbered 2dis should have to be signed as bypasses. It's more important that they fit more generally, into the category of having two junctions with the 2di of which they originated from. Similarly, it's not important that odd numbers are true spurs, just that they only have one junction with their associated 2di.

Well, not bad for not using Wikipedia 

[Perfxion]

610(TX) is a beltway completely inside another beltway inside of another beltway being built. Hard to use the word bypass when you never bypass Houston on it.

[SectorZ]

I-290 in Massachusetts would beg to differ, but that is the exception more than the rule.

[Life in Paradise]

I would use a textbook example of a bypass to be I-475 around Macon, GA.  I-75 goes into Macon and comes out, and I-475 bypasses the city, and actually is the shorter route to keep going south.  Matter of fact, I can't remember the last time that I have gone through Macon going north or south.

[jp the roadgeek]

I-495 (the LIE), I-278, and I-678 are hardly bypasses.  I 295 and I-695 in NY, I-684 and I-691 are more of a connection between its parent and another interstate. I-291 in MA is a spur into downtown Springfield, and I-293 passes through downtown Manchester while its parent serves as a bypass.  Once proposed I-484 would have met the same criteria as the others above.

[PHLBOS]

Rand McNally's typically defines even 3DIs as routes that go through or around a city.  Such notation is listed on their maps & atlases.

[jon daly]

I-290 in Massachusetts would beg to differ, but that is the exception more than the rule.

Is I-395 in CT & MA even a spur?

[sparker]

Personally, I'd consider any 3di that connected a 2di, parent or not, to its continuation at the other side of a metro area to be a bypass -- at least functionally.  A beltway could be considered to include a bypass function -- like I-270 around Columbus being a bypass for I-71 traffic wishing to avoid the city center; in that instance, the beltway would simply be two arcs with two common connections.  Of course, there are "true", or dedicated bypasses; I-475 around Macon, GA would certainly qualify, as would I-840 around Nashville -- although one sticks close to the metro center, while the other gives it a very wide berth.  I.e.: a beltway can also be a bypass, but a 2-point "actual" bypass isn't a beltway per se. 

Of course, then there are the 3/4 circles such as Salt Lake City and the nascent 215 Vegas loop -- that sort of fit in between -- since their configuration allows them to function as a "double bypass" -- I-215/UT can function as a bypass for both I-15 and I-80.  Actually, in practice it seems to come down to semantics -- the terms are like the English language -- consistent until an exception comes along -- such as I-635 around Dallas, which has one of its ends within the DFW airport grounds (which technically shouldn't happen with an even-prefixed 3di) -- or even I-495, which stub-ends out near the Hamptons (or the inverse, such as CA's I-780).  Presently, it appears that those in officialdom who would serve as concept enforcement have elected to ignore deviations from the "norm" -- as long as the system seems to function reasonably well. 

[msubulldog]

One I would consider more of a bypass would be I-610 in New Orleans.

Would you say the same for I-210 around Lake Charles, especially with what I have heard about the sub-standard bridge on I-10 across the lake?

[hbelkins]

like I-270 around Columbus being a bypass for I-71 traffic wishing to avoid the city center

If I want to bypass downtown Columbus if traveling on I-71, or US 23 for that matter, I'm going to use OH 315, not I-270 all the way around.

[Flint1979]

I-490 in Rochester sure as heck isn't a bypass. It goes right through downtown.

I'm not of the belief that even-numbered 2dis should have to be signed as bypasses. It's more important that they fit more generally, into the category of having two junctions with the 2di of which they originated from. Similarly, it's not important that odd numbers are true spurs, just that they only have one junction with their associated 2di.

Take I-290 in Buffalo, for example. It's hard to say if it should be an even or an odd number, since it facilitates through traffic but doesn't connect to I-90 on both ends. Beltways (or other bypasses) should always be even numbers; spurs should always be odd numbers. But some 3dis don't fit neatly into either category.

The way I see it with I-490 in Rochester is that I-90 is the bypass and I-490 actually serves Rochester. It's like that here too I-675 serves downtown Saginaw but was really built to bypass the original Zilwaukee Bridge and I-75 bypasses the city, same with I-475 in Flint it goes right through the heart of the city of Flint and I-75 bypasses most of the city of Flint but not by much. I-496 goes through Lansing and I-96 bypasses it.

I-290 in Buffalo I think that's there as a route to bypass going through Buffalo to get to Canada, I-90 never actually enters the city of Buffalo either. I don't know what that one should be but it does end at I-190 and I never understood the need for I-990 really does there really need to be an Interstate highway there? I guess some of them it's hard to decide.

[vdeane]

I-990 was supposed to go up to Lockport but never got finished.

[webny99]

Of course I-490 isn't meant as a bypass of Rochester itself, but it does connect to I-90 on both ends. So it is an alternate to I-90, and a fairly interesting one at that.

The function (and strategic importance) of I-290 was never in question. I-990, on the other hand, I could see how one might regard it as unimportant. Keep in mind it was meant to go to Lockport (EDIT: I see vdeane has noted this as well), and had it done so, it would have been much more effective as part of the interstate system. It's a shame that plan was cancelled; it would have been a nice addition to Buffalo's freeway network and perhaps have brought much needed economic stimulus to Niagara County.

[Beltway]

The function (and strategic importance) of I-290 was never in question. I-990, on the other hand, I could see how one might regard it as unimportant. Keep in mind it was meant to go to Lockport (EDIT: I see vdeane has noted this as well), and had it done so, it would have been much more effective as part of the interstate system. It's a shame that plan was cancelled; it would have been a nice addition to Buffalo's freeway network and perhaps have brought much needed economic stimulus to Niagara County.

But would the unbuilt portion of the Lockport Expressway have been I-990?
I didn't think that was proposed.

[jwolfer]

I-10 starts about 4 miles east of 295 at the junction with i95. 295 was a partial beltway around the west side of Jacksonville connecting to i95 on both ends. The west beltway was fully completed ~1977.

The east bestways first part was the NE quadrant. And the most expensive and biggest engineering portionwas the Dames Point Bridge opening around 1990. The beltway was functionally completed sometime in the early 2000s but it was not up to interstate standards until several years ago.. it was signed SR 9A, the secret designation of the entire beltway. 295 signed went up circa 2012

Z981

[webny99]

The function (and strategic importance) of I-290 was never in question. I-990, on the other hand, I could see how one might regard it as unimportant. Keep in mind it was meant to go to Lockport (EDIT: I see vdeane has noted this as well), and had it done so, it would have been much more effective as part of the interstate system. It's a shame that plan was cancelled; it would have been a nice addition to Buffalo's freeway network and perhaps have brought much needed economic stimulus to Niagara County.

But would the unbuilt portion of the Lockport Expressway have been I-990?
I didn't think that was proposed.

I always thought so. Considering the potential routings, I can't imagine what other number it would've used. But those that have been around for longer could confirm

[Beltway]

But would the unbuilt portion of the Lockport Expressway have been I-990?  I didn't think that was proposed.

I always thought so. Considering the potential routings, I can't imagine what other number it would've used. But those that have been around for longer could confirm

But it would have been a dedesignation from the Interstate system.  And I don't recall seeing anything about that being done.

It could have been similar to I-795 in Maryland, where one section (I-695 to west of Owings Mills Blvd.) was funded as an Interstate highway and the other section (to west of Reisterstown, Md.) was funded as a primary highway, but after it was all completed all of it was designated as I-795.

[wxfree]

Is there an agreed-upon definition of what is considered to be a bypass?  To me a bypass is a road the use of which is beneficial compared with use of the business route, or parent Interstate, for driving from one side of town to the other.  A US highway freeway, which may also be partly or entirely Interstate, is a bypass of the old route even if it still goes through downtown, or goes around town and is significantly longer, because it's better than going through the traffic signals on the business route.

A three-digit Interstate, by my definition, is a bypass only if using it to get from one side of town to the other is beneficial (at least some of the time) compared with driving straight through on the parent route, or at least one other Interstate through route.  If it's useful mainly for local traffic, or for getting from one spoke route to another without going further into town, I don't consider that to be a bypass.  To me, that's more of a cut-through.

Using the example of Atlanta.  I'd consider I-285 to be a bypass if it's a better way to get across town than I-85, or at least another Interstate, such as I-20 or I-75.  If it's useful to get from south on I-85 to east on I-20 without going further into town, I wouldn't consider that to mean it's a bypass.