Exchanging 3di's for 2di's

[Revive 755]

On the contrary, it makes no sense for a route to just spontaneously change number. If it was left as it was, motorists would drive straight through an interchange, on the mainline of a highway, and all of a sudden find that the number has changed for no apparent reason. So, it made perfect sense for I-26 to assimilate I-181 like that.

Now, as for the fact that I-26 travels more north-south than it does east-west... that's an actual logic error, but the lack of available numbers in the region meant it was either give it an even number and sign it east-west or give it a very out of place odd number.
Although, I dunno, I think I might actually like it better if it were I-67 (the closest and highest available odd number).

But there are so many corridors proposed/available where I-67 would be in the proper place:  Montgomery AL to I-10, US 31 from Indy to South Bend, or US 131 in Michigan.  Better to make the current I-26 from I-385 to the Virginia state line into a southern I-79, and have I-26 replace I-385.

Regarding the original topic, I think I-10 or I-17 replaced an even I-x10 in Phoenix.

[FLRoads]

On the contrary, it makes no sense for a route to just spontaneously change number. If it was left as it was, motorists would drive straight through an interchange, on the mainline of a highway, and all of a sudden find that the number has changed for no apparent reason. So, it made perfect sense for I-26 to assimilate I-181 like that.

Now, as for the fact that I-26 travels more north-south than it does east-west... that's an actual logic error, but the lack of available numbers in the region meant it was either give it an even number and sign it east-west or give it a very out of place odd number.
Although, I dunno, I think I might actually like it better if it were I-67 (the closest and highest available odd number).

But there are so many corridors proposed/available where I-67 would be in the proper place:  Montgomery AL to I-10, US 31 from Indy to South Bend, or US 131 in Michigan.  Better to make the current I-26 from I-385 to the Virginia state line into a southern I-79, and have I-26 replace I-385.

Regarding the original topic, I think I-10 or I-17 replaced an even I-x10 in Phoenix.

I agree with you on the possibilities on where the number 67 could go.  I also like your idea about renumbering of I-26 into a southern I-79.  Even though it would be located west of I-77, it would fit into the system better than the current I-26.  I also like your idea about I-26 taking over I-385.  Now to quote duke87, would you have it completely assimilate I-385 or would you have it end at I-85 with the original I-385 still being a spur into Greenville??  Just curious.

As far as your question about the replacement in Phoenix, an I-410 was originally proposed on the alignment that the current I-10 is on between the two I-17 interchanges near downtown.  But the route was nixed in favor of I-10.

[Alex]

According to Scott Kozel's Roads to the Future, the I-95 designation replaced I-495 in 1977 on the eastern half of the Beltway when I-395 took over Shirley.  The cosigning occurred in 1989.

http://www.roadstothefuture.com/Capital_Beltway.html

Many signs even in 1993 had Interstate 495 co-signed as an afterthought. There were guide signs for Interstate 95 with a small Interstate 495 panel posted next to them. It did not take long after that for Interstate 495 to be reintegrated onto the eastern half of the beltway.

[FLRoads]

On the contrary, it makes no sense for a route to just spontaneously change number. If it was left as it was, motorists would drive straight through an interchange, on the mainline of a highway, and all of a sudden find that the number has changed for no apparent reason. So, it made perfect sense for I-26 to assimilate I-181 like that.

There are other great examples of interstate routes changing numbers on the mainline:

Interstate 494 becomes 694 (and vice versa) at the full-cloverleaf interchange with I-94 east of St. Paul, MN:
http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=44.948384~-92.9597&style=h&lvl=15&tilt=-90&dir=0&alt=-1000&scene=6213915&phx=0&phy=0&phscl=1&encType=1

Interstates 280 and 680 swap numbers at the US 101 stack interchange in San Jose, CA:
http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=37.339276~-121.851876&style=h&lvl=16&tilt=-90&dir=0&alt=-1000&scene=5911709&phx=0&phy=0&phscl=1&encType=1

Even though these are 3di to 3di number changes, it is still a change of a route number on the main carriageways of an interstate highway.

[Duke87]

I also like your idea about I-26 taking over I-385.  Now to quote duke87, would you have it completely assimilate I-385 or would you have it end at I-85 with the original I-385 still being a spur into Greenville??  Just curious.

I'd have I-26 eat the whole thing all the way into Greenville, if we were going to do that.

Although, no, I wouldn't reroute I-26 that way.

Looking at it, it might make more sense for the part of 385 north of the junction with 185 to be part of 185, with the rest either remaining 385 or being an x26... but I'm generally not a fan of renumbering highways just 'cause. It causes too much confusion and is a waste of money. Renumbering really ought to only take place as a result of highways being extended where a new longer highway absorbs a shorter existing one.

[FLRoads]

Yes, because we need to have as few interstate numbers as possible in this country.

[mightyace]

There are other great examples of interstate routes changing numbers on the mainline:

I'm sure I can pick up several given time...  

Here are two that immediately come to mind:

In the Quad Cities area of Illinois and Iowa near Moline, IL you have a switch between I-80 and I-74/280 on the east/west mainline and I-74 and I-80 on the north/south mainline.

Near Youngstown, OH @ Ohio Turnpike Exit 218, both the Turnpike mainline and a freeway exchange I-76 and I-80.  The freeway is I-76 west of the interchange toward Akron and is I-80 east of the interchange toward northern Youngstown and northern Pennsylvania.

The Ohio turnpike is I-80 northwest of the interchange toward Cleveland and is I-76 southwest of the interchange towards the Pennsylvania Turnpike and Pittsburgh.

[akotchi]

A few more . . .

I-395 and I-290 change at the Mass Pike.

I-76 and I-276 at Valley Forge, PA

I-287 and NJ 440 in Woodbridge, NJ (even though one is not an interstate)

[FLRoads]

Okay, getting back to the root of this topic, what do others think about existing 3di's getting overtaken by 2di's (via extension and otherwise)??

[mightyace]

Okay, getting back to the root of this topic, what do others think about existing 3di's getting overtaken by 2di's (via extension and otherwise)??

I prefer it for long[er] distance routes.

For example, I-99 replacing I-390 in New York.

Or, how about, a second I-85 replacing I-476 along the PA Turnpike Northeast Extension.   I-476 is way too long! IMHO  Also, since it now extends up to Scranton it should at least be an odd number since it's really a spur.

[ctsignguy]

Maybe what should be done is AASHTO rip down all the current Interstate numbers....and assign us signgeeks to redo the grid so the numberings make more sense given how many Interstates there are now (and proposed/under construction) than planned back in the mid-50s.... (and get rid of that damned I-99 in PA!!!)

[FLRoads]

I totally agree with that one!

[74/171FAN]

Another planned 3di for a 2di in Virginia is I-581 for I-73(if VDOT ever gets the money to build it)

[deathtopumpkins]

If I-66 wasn't supposed to be extended, I would make it a 3di... maybe another x95. It sure shouldn't be a 2di though, as it only runs through the top of the state of Virginia. Never even crosses state lines.

And I just realized that that is the opposite of this thread... 

[mightyace]

If I-66 wasn't supposed to be extended, I would make it a 3di... maybe another x95. It sure shouldn't be a 2di though, as it only runs through the top of the state of Virginia. Never even crosses state lines.

True, DTP, it never crosses state lines, but it does enter the District of Columbia for about a mile and a half.   See aaroad's interstate guide at  http://www.interstate-guide.com/i-066.html

[deathtopumpkins]

Meh... close enough. It's pretty much just one big interchange inside D.C.

[Sykotyk]

I can't believe nobody has named the biggest 'route number change' out there: I-80 and I-76 in Ohio. But that's mostly due to the fact the Ohio Turnpike is the true 'mainline'.

Sykotyk

[timhomer2009]

Isn't I-99 in PA just an elaborate monument to Bud Shuster?

[mightyace]

Isn't I-99 in PA just an elaborate monument to Bud Shuster?

Pretty much.   

[Terry Shea]

I can't believe nobody has named the biggest 'route number change' out there: I-80 and I-76 in Ohio. But that's mostly due to the fact the Ohio Turnpike is the true 'mainline'.

Sykotyk

Actually mightyace did bring that up several posts before yours.   

[ComputerGuy]

How about exchanging I-182 and I-184 for a new extended I-82, from the Tri-Cities to Boise via Walla Walla and Lewiston, ID?

[njroadhorse]

I'm surprised nobody's mentioned I-279 and I-79.  Technically, these routes are backwards of what AASHTO defines, and originally I-79 was supposed to go into Pittsburgh.  The southern section was originally defined as I-79, and once the section on the north side of the city was completed, then I-79 would be a through route through Pittsburgh.  Instead, they switch them, much to my chagrin .

[Duke87]

I'm surprised nobody's mentioned I-279 and I-79.  Technically, these routes are backwards of what AASHTO defines, and originally I-79 was supposed to go into Pittsburgh.  The southern section was originally defined as I-79, and once the section on the north side of the city was completed, then I-79 would be a through route through Pittsburgh.  Instead, they switch them, much to my chagrin

Personally, I think it makes more sense for the mainline to take the shorter route, whether that means going through the city or bypassing it. Simply because long distance traffic will tend to follow the mainline, and thus if you make the longer route the mainline, you're going to send people the long way around, wasting gas and travel time. It doesn't make a difference for traffic going to the city, they'll follow whichever route goes there regardless.
As for the supposed "benefit" of a city getting a 2di over a 3di... meh, it's all in people's heads. Practically, it makes no difference. Sending 79 through Pittsburgh as opposed to 279 wouldn't boost business in the city any, though it would likely boost congestion a bit. Not to mention that doing that would mean routing 79 along a pair of single lane ramps south of the city (never a good thing).

Similarly, swapping 70 and 270 around St. Louis would make sense (270's a lot shorter and avoids downtown)... though the western junction between the two would need to be fixed to avoid the single lane ramp issue.

[Sykotyk]

I'm surprised nobody's mentioned I-279 and I-79.  Technically, these routes are backwards of what AASHTO defines, and originally I-79 was supposed to go into Pittsburgh.  The southern section was originally defined as I-79, and once the section on the north side of the city was completed, then I-79 would be a through route through Pittsburgh.  Instead, they switch them, much to my chagrin

Personally, I think it makes more sense for the mainline to take the shorter route, whether that means going through the city or bypassing it. Simply because long distance traffic will tend to follow the mainline, and thus if you make the longer route the mainline, you're going to send people the long way around, wasting gas and travel time. It doesn't make a difference for traffic going to the city, they'll follow whichever route goes there regardless.
As for the supposed "benefit" of a city getting a 2di over a 3di... meh, it's all in people's heads. Practically, it makes no difference. Sending 79 through Pittsburgh as opposed to 279 wouldn't boost business in the city any, though it would likely boost congestion a bit. Not to mention that doing that would mean routing 79 along a pair of single lane ramps south of the city (never a good thing).

Similarly, swapping 70 and 270 around St. Louis would make sense (270's a lot shorter and avoids downtown)... though the western junction between the two would need to be fixed to avoid the single lane ramp issue.

True, but that doesn't stop other interstates from a one-lane ramp. I-80 in Nebraska has a one-lane stretch in both directions with the I-76 junction (I-80 west to I-76 is the mainline).

Still, anybody looking for the 'fastest way' will take I-270, regardless. Only those not prone to look at directions and repeats the mantra "follow I-70 to Denver" for example, will find themselves in downtown St. Louis.

Sykotyk

[Duke87]

Still, anybody looking for the 'fastest way' will take I-270, regardless. Only those not prone to look at directions and repeats the mantra "follow I-70 to Denver" for example, will find themselves in downtown St. Louis.

You'd be surprised how many people that latter description represents. When driving on unfamiliar roads that they need directions for, people will tend to favor a simpler route over a shorter/faster one. "Follow I-70 west" is a lot easier to remember than "Follow I-70 west, when you're approaching St Louis, get off onto I-270 west, then get back onto I-70 west".
And when you tell someone that that's shorter, they might scratch their head and wonder "well, if it's shorter, than why'd they make I-70 go the other way?" And they'd have an excellent point.

Putting up guide signs which advise long distance travelers to go the other way does help, though.