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

[Beltway]

Is there an agreed-upon definition of what is considered to be a bypass? 

The US-29 freeway functions as a traffic bypass at Danville, VA, but most of the length is within the City of Danville, as the city has more extensive area than most cities of its population, and that portion is named the Danville Expressway because Danville Bypass would be technically incorrect.

It clearly is a bypass of the Danville urbanized area, but the argument would be whether it actually bypasses the City of Danville, geographically it does not.

Regarding the "expressway" portion of the name, the name dates back to the 1960s when it was first added to regional thoroughfare plans, and back then the FHWA distinction between "freeway" and "expressway" was not yet very widely known and practiced around the country.

[wxfree]

Is there an agreed-upon definition of what is considered to be a bypass? 

The US-29 freeway functions as a traffic bypass at Danville, VA, but most of the length is within the City of Danville, as the city has more extensive area than most cities of its population, and that portion is named the Danville Expressway because Danville Bypass would be technically incorrect.

It clearly is a bypass of the Danville urbanized area, but the argument would be whether it actually bypasses the City of Danville, geographically it does not.

Regarding the "expressway" portion of the name, the name dates back to the 1960s when it was first added to regional thoroughfare plans, and back then the FHWA distinction between "freeway" and "expressway" was not yet very widely known and practiced around the country.

I'm not familiar with that road, but looking at a map it seems like what I would call a bypass, because it looks like the freeway is a better way to get from north of town to south of town than the business route.  That's what defines a bypass to me, whether another road, generally the old route or parent route, is bypassed by a better route between two places where they meet.  Whether it's rural or serves the same city doesn't enter into my consideration, because I just look at the two points where the routes intersect and which way is the better way to get between those points.

[vdeane]

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.

I've never heard of it being anything other than I-990.  No idea how it would have been funded, not that anyone outside of roadgeeks and DOTs cares beyond it having a red, white, and blue shield or not, and I-990 is relatively new (compared to just about everything else in NY), so it was probably never eligible for the full 90% interstate funding.

Extensions north of the original end at French Road never got off the ground, so it probably never got to the level of AASHTO or FHWA.  Even the extension to NY 263 was only done to relive traffic using French Road as a connector when it became clear that the full concept wouldn't be built in the foreseeable future.

[kkt]

There are lots of 3dis with even first digits which are not bypasses.  Of course I grew up in the San Francisco Bay Area, which there's only one 2di and there have been (at various times) nine different 3di children of it, none of which really functions as a bypass for the metro area.

The interstate convention is really just that the even first digit 3dis meet another interstate at both ends, and even that convention gets broken a lot.

[TheStranger]

There are lots of 3dis with even first digits which are not bypasses.  Of course I grew up in the San Francisco Bay Area, which there's only one 2di and there have been (at various times) nine different 3di children of it, none of which really functions as a bypass for the metro area.

280 and 680 are bypasses to some extent, but NOT of the parent route.  IIRC, the original 1950s-1968 routing of 280 that included the unbuilt freeway paralleling 19th Avenue/Junipero Serra Boulevard north of Brotherhood Way iN SF, that would have had both termini at US 101 as an effective bypass of downtown San Francisco and the Peninsula - though 280 as it ended up in San Jose goes through the south edge of downtown.  (I've seen some 1950s planning maps on that one Flickr page - Eric Fischer's page I think - that incorporated today's Route 85 south of Cupertino as part of the proposed Junipero Serra/280 corridor of the time)

680 was more of a belt route when it incorporated today's 780 from the 1950s to 1976, but with the addition of the northernmost part of former Route 21 then, 680 does seem to be a bypass of Vallejo and Oakland for travelers heading to San Jose from points north like Napa and Sacramento.  Had the 238 freeway along Mission Boulevard been constructed, 680 and the MacArthur Freeway portion of 580 would have combined with it to provide an parallel alternate route to the Nimitz Freeway between San Jose and Oakland.

[Beltway]

The interstate convention is really just that the even first digit 3dis meet another interstate at both ends, and even that convention gets broken a lot.

What about Interstate 3di that junction at least 2 other Interstates but then continue to an open end?  There are at least 15 of them.

[Pink Jazz]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

[Flint1979]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

It might have something to do with I-264 being planned as an Interstate through downtown Norfolk. Norfolk is actually the principal city in that metro area even though Virginia Beach is now more populated. Norfolk use to be more populated until sometime in the 1980's.

[Kulerage]

They should be considered the universal definition of "loops". Beltways and By-Passes fit under that word IMO.

[kphoger]

Is it fair to say that beltway is simply a subset of bypass?
People don't call them a bypass because they use a more specific term.

[Pink Jazz]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

It might have something to do with I-264 being planned as an Interstate through downtown Norfolk. Norfolk is actually the principal city in that metro area even though Virginia Beach is now more populated. Norfolk use to be more populated until sometime in the 1980's.

Still, that doesn't make it a bypass considering it goes right through the core of the principal city.

[hbelkins]

Keep in mind that the original number of the eastern portion of I-264 was VA 44. It was later given an interstate number, and I guess it made sense to extend I-264 instead of giving it another number.

[webny99]

Is it fair to say that beltway is simply a subset of bypass?
People don't call them a bypass because they use a more specific term.

Sounds reasonable, considering beltways can, by nature, be used as bypasses, but not vice versa.

[PurdueBill]

I-271, I-280(OH), and I-290(MA) are among many good examples of 3DIs with even first digits that act as connectors between members of different 2DI families (I-71/I-90, I-80&90/I-75, and I-90/I-495 respectively) that have the even first digit because they have both ends at an Interstate, even though not the same 2DI or even a member of the same 2DI family.  Not that far away in Mass., there is the interesting situation of I-195 ending at I-495 and vice versa, which wasn't always the original plan but has been the case for a long time.  195 ends at an Interstate at both ends but it's more trouble than it's worth to renumber.  It is conceivable that one or the other of 495 or 195 could best be extended as far down MA 25 as possible if Mass really wanted to, but while it seems sensible to extend 495 as it's already the longer one, the numbering convention would say to extend 195 because its end would not be at another Interstate.
So, there seem to be general trends but plenty of exceptions.  But generally 3DIs with even first digits tend to be bypasses, especially if a beltway is considered as a subset of bypasses.  (The craziest one in my mind is probably I-287 having both ends at I-95 while it multiplexes with its parent for miles in between.  Crazy!)

[Flint1979]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

It might have something to do with I-264 being planned as an Interstate through downtown Norfolk. Norfolk is actually the principal city in that metro area even though Virginia Beach is now more populated. Norfolk use to be more populated until sometime in the 1980's.

Still, that doesn't make it a bypass considering it goes right through the core of the principal city.

A 3-di doesn't always have to be the bypass. Like in Michigan, I-475 goes through downtown Flint rather than bypassing it as I-75 does the bypassing. I-496 goes through downtown Lansing while I-96 bypasses it. I-675 goes through downtown Saginaw with I-75 bypassing it but I-675's actual purpose was to bypass the original Zilwaukee Bridge which was a drawbridge that caused delays for multiple miles but the high level Zilwaukee Bridge replaced it about 30 years ago meaning the original purpose of I-675 was no longer needed but it does serve as a through route for I-75 at times when the Zilwaukee Bridge is closed and serves downtown Saginaw. My point here is that all these even 3-di's travel through the downtown's of the principal cities rather than bypass them, the parent route is the bypass in this case.

[Flint1979]

One of my favorite bypasses is I-475 in Georgia bypassing Macon now that is a true bypass right there. It shaves off about 5 or 6 miles.

[ilpt4u]

Chicago and I-290 is not much of a bypass, but it does connect to I-90 on both ends. Granted, there has been chatter on the Fictional board to have the Chicago I-290 designation go away...

I-471 in Cincy isn't much of a bypass, either. It does connect two interstates together (275 and 71), but on a map and in function, works more like a Spur of Downtown I-71, giving a freeway to the Beltway to the SE as opposed to the mainline 71/75 to the SW. I would have given it an (odd)3di...371 sounds good

Then you have I-355 in Suburban Chicago, which probably does function more like a Bypass, especially if the IL 53 Lake County Extension is ever built, yet ISTHA wanted an (odd)3di, and got one

Sometimes I think the Even/Bypass vs Odd/Spur idea is more Guidelines than a hard rule

[ftballfan]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

It might have something to do with I-264 being planned as an Interstate through downtown Norfolk. Norfolk is actually the principal city in that metro area even though Virginia Beach is now more populated. Norfolk use to be more populated until sometime in the 1980's.

Still, that doesn't make it a bypass considering it goes right through the core of the principal city.

A 3-di doesn't always have to be the bypass. Like in Michigan, I-475 goes through downtown Flint rather than bypassing it as I-75 does the bypassing. I-496 goes through downtown Lansing while I-96 bypasses it. I-675 goes through downtown Saginaw with I-75 bypassing it but I-675's actual purpose was to bypass the original Zilwaukee Bridge which was a drawbridge that caused delays for multiple miles but the high level Zilwaukee Bridge replaced it about 30 years ago meaning the original purpose of I-675 was no longer needed but it does serve as a through route for I-75 at times when the Zilwaukee Bridge is closed and serves downtown Saginaw. My point here is that all these even 3-di's travel through the downtown's of the principal cities rather than bypass them, the parent route is the bypass in this case.

Throw in the unsigned I-296 which isn't even a bypass, but is a connector from I-96 (which bypasses Grand Rapids) to I-196 (which runs on the north end of downtown Grand Rapids). The only part that's not concurrent with US-131 is a pair of LONG slip roads from EB I-96 to SB US-131 and NB US-131 to WB I-96.

[Flint1979]

I-264 in the Hampton Roads area of Virginia seems to be the opposite of a bypass - it is the main route through Virginia Beach as well as the route through Downtown Norfolk.  I-64 on the other hand barely enters Virginia Beach and goes around Downtown Norfolk via Chesapeake.

It might have something to do with I-264 being planned as an Interstate through downtown Norfolk. Norfolk is actually the principal city in that metro area even though Virginia Beach is now more populated. Norfolk use to be more populated until sometime in the 1980's.

Still, that doesn't make it a bypass considering it goes right through the core of the principal city.

A 3-di doesn't always have to be the bypass. Like in Michigan, I-475 goes through downtown Flint rather than bypassing it as I-75 does the bypassing. I-496 goes through downtown Lansing while I-96 bypasses it. I-675 goes through downtown Saginaw with I-75 bypassing it but I-675's actual purpose was to bypass the original Zilwaukee Bridge which was a drawbridge that caused delays for multiple miles but the high level Zilwaukee Bridge replaced it about 30 years ago meaning the original purpose of I-675 was no longer needed but it does serve as a through route for I-75 at times when the Zilwaukee Bridge is closed and serves downtown Saginaw. My point here is that all these even 3-di's travel through the downtown's of the principal cities rather than bypass them, the parent route is the bypass in this case.

Throw in the unsigned I-296 which isn't even a bypass, but is a connector from I-96 (which bypasses Grand Rapids) to I-196 (which runs on the north end of downtown Grand Rapids). The only part that's not concurrent with US-131 is a pair of LONG slip roads from EB I-96 to SB US-131 and NB US-131 to WB I-96.

It's like that in all Michigan cities except Detroit I guess.