AARoads Forum

National Boards => General Highway Talk => Topic started by: KeithE4Phx on October 06, 2021, 01:04:17 AM

Title: Alternate Interstate Highways?
Post by: KeithE4Phx on October 06, 2021, 01:04:17 AM
Is this a Wisconsin thing, or does it go on more than I thought?  The attached Google Map photo shows northbound US 151 signed as "Alternate I-41" at County TC, near Lamartine, southwest of Fond du Lac.  It's a 4-lane road, but not a freeway, so how could it be considered an "alternate freeway?"

This is a new one on me.  I've never seen this in person.

https://www.google.com/maps/@43.72534,-88.5764488,3a,37.5y,62.5h,89.38t/data=!3m6!1e1!3m4!1s8pPMOtXNfQT4mSbUcstsbQ!2e0!7i13312!8i6656
Title: Re: Alternate Interstate Highways?
Post by: Hot Rod Hootenanny on October 06, 2021, 01:15:17 AM
Ohio does this with I-70 (US 40 near Dayton-Springfield)
Title: Re: Alternate Interstate Highways?
Post by: Bruce on October 06, 2021, 01:26:04 AM
There's a sign for "ALT I-5" on Denny Way in Seattle, which is meant to show an alternate path to reach I-5 rather than an alternate for I-5.

https://goo.gl/maps/VrWT2rRMLP2UjoFm7
Title: Re: Alternate Interstate Highways?
Post by: FrCorySticha on October 06, 2021, 09:07:47 AM
Wisconsin has marked alternate routes for all its Interstate highways along parallel highways, and I wish more states would follow their lead. If part or all of an Interstate ever has to be shut down due to serious accident, weather, damage to the road, etc., it allows for easily redirecting traffic around the closure. Also, it gives another option for traffic that might not fit on the Interstate due to oversize, especially over-height freight.
Title: Re: Alternate Interstate Highways?
Post by: 1 on October 06, 2021, 09:17:08 AM
This sign is interesting, as it's part of New Hampshire's system, but it's in Massachusetts.
https://www.google.com/maps/@42.7339351,-71.1920521,3a,15y,216.3h,87.72t/data=!3m7!1e1!3m5!1sOMrtkkDco21OrlH1CPA7fg!2e0!5s20191001T000000!7i16384!8i8192 (https://www.google.com/maps/@42.7339351,-71.1920521,3a,15y,216.3h,87.72t/data=!3m7!1e1!3m5!1sOMrtkkDco21OrlH1CPA7fg!2e0!5s20191001T000000!7i16384!8i8192)
Title: Re: Alternate Interstate Highways?
Post by: wanderer2575 on October 06, 2021, 09:24:56 AM
Western Michigan has alternate routes posted for portions of freeways -- not just Interstates but also for the US-31, US-131, and M-6 freeways.  A lot of these are along former route alignments that predated the freeways.  Instead of an ALT or ALTERNATE banner, Michigan uses a black-on-orange EMERGENCY banner.  I don't know why it isn't done throughout the rest of the state.

Example:  https://goo.gl/maps/FUdHMLYSzoxQMMnt9
Title: Re: Alternate Interstate Highways?
Post by: OCGuy81 on October 06, 2021, 09:36:40 AM
Wisconsin is the one state where I've seen it used very widely.

I don't believe I've ever seen any Alternate being signed in Oregon or California.
Title: Re: Alternate Interstate Highways?
Post by: GaryV on October 06, 2021, 10:14:06 AM
Western Michigan has alternate routes posted for portions of freeways -- not just Interstates but also for the US-31, US-131, and M-6 freeways.  A lot of these are along former route alignments that predated the freeways.  Instead of an ALT or ALTERNATE banner, Michigan uses a black-on-orange EMERGENCY banner.  I don't know why it isn't done throughout the rest of the state.

Example:  https://goo.gl/maps/FUdHMLYSzoxQMMnt9

There are Emergency I-75 signs along surface streets in Oakland Co.
Title: Re: Alternate Interstate Highways?
Post by: Dirt Roads on October 06, 2021, 10:33:12 AM
There are Alternate I-40 banners along I-87, US-264 and I-95 to get around the long-term I-40 widened projects between the Raleigh Beltline and [now south of] McGees Crossroads.  When they were first installed, you could follow them all the way.  They've been up so long now that I doubt that you could find your way using signs alone.

Did I actually say I-87?   :pan:
Title: Re: Alternate Interstate Highways?
Post by: jp the roadgeek on October 06, 2021, 10:35:16 AM
There are a few ALT I-84 and ALT I-91 LGS’s in CT along I-691 and CT 9
Title: Re: Alternate Interstate Highways?
Post by: hbelkins on October 06, 2021, 12:33:36 PM
There are a bunch of old alternate signs for I-71 and I-75 in Cincinnati.

There are also a few remnant alternate signs for I-75 along US 25E in Tennessee, dating back from the I-75 was closed between Knoxville and the state line for a major break in pavement.

Most of the referenced alternate signs are really for emergency incident management, with some even being signed (as noted) with "EMERGENCY" banners.
Title: Re: Alternate Interstate Highways?
Post by: HighwayStar on October 06, 2021, 03:26:41 PM
I am a big fan of this approach. Along with the usual advantages of keeping US highways separate from the interstate system, they can post them like this as "emergency" routes for the interstates.
Title: Re: Alternate Interstate Highways?
Post by: TheHighwayMan394 on October 06, 2021, 03:30:07 PM
Minnesota started implementing the system, but never finished. I-35 south of the metro and I-94 northwest of it have signed alternates, but never seen them on I-90 or I-35 north of the Twin Cities. In addition, some of Wisconsin's system is posted in the far eastern parts of the state.
Title: Re: Alternate Interstate Highways?
Post by: hbelkins on October 06, 2021, 03:33:58 PM
I'm sure a lot of this has been discussed in the past -- Pennsylvania's color-coded detours, Missouri's "Incident Bypass Route" signage, etc.

Kentucky was looking to sign something in the western part of the state. There's a lot of work being done on I-24, and a lot of truck wrecks in the work zone that caused issues. I found a bunch of examples from Street View (many from Wisconsin and Michigan) to send to my colleague in Paducah for examples.
Title: Re: Alternate Interstate Highways?
Post by: HighwayStar on October 06, 2021, 03:38:23 PM
I'm sure a lot of this has been discussed in the past -- Pennsylvania's color-coded detours, Missouri's "Incident Bypass Route" signage, etc.

Kentucky was looking to sign something in the western part of the state. There's a lot of work being done on I-24, and a lot of truck wrecks in the work zone that caused issues. I found a bunch of examples from Street View (many from Wisconsin and Michigan) to send to my colleague in Paducah for examples.

This should be a national standard, each state having a different signage is confusing.
Title: Re: Alternate Interstate Highways?
Post by: US 89 on October 06, 2021, 03:48:39 PM
The only place I've ever seen this myself is in Kansas City, where I-670 was signed as Alternate I-70. Although looking at street view, this may not be the case anymore?
Title: Re: Alternate Interstate Highways?
Post by: LM117 on October 07, 2021, 05:00:53 AM
There are Alternate I-40 banners along I-87, US-264 and I-95 to get around the long-term I-40 widened projects between the Raleigh Beltline and [now south of] McGees Crossroads.  When they were first installed, you could follow them all the way.  They've been up so long now that I doubt that you could find your way using signs alone.

Did I actually say I-87?   :pan:

You can also find an  "ALT ROUTE" I-40 sign at the end of the off-ramp from I-40 West to US-117 at the interchange between Warsaw and Magnolia (Exit 369). That one's been there long before the Raleigh projects started.
Title: Re: Alternate Interstate Highways?
Post by: mukade on October 07, 2021, 05:43:50 PM
Indiana uses white on blue "Emergency Detour" signs at certain places along I-65, I-69, and I-469. Fort Wayne and Lafayette are where I have seen them - not sure if there are other ones.

https://www.google.com/maps/@41.1307723,-85.1590783,3a,15y,344.1h,89.3t/data=!3m7!1e1!3m5!1swwTn1Mwhz82lKdtXVE8y7g!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwwTn1Mwhz82lKdtXVE8y7g%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D63.50002%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656 (https://www.google.com/maps/@41.1307723,-85.1590783,3a,15y,344.1h,89.3t/data=!3m7!1e1!3m5!1swwTn1Mwhz82lKdtXVE8y7g!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwwTn1Mwhz82lKdtXVE8y7g%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D63.50002%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656)
Title: Re: Alternate Interstate Highways?
Post by: GaryA on October 07, 2021, 06:44:06 PM
Los Angeles has a short ALT I-5/I-10/CA 60:  https://goo.gl/maps/MbVe8Cp4WZpCePkR8

Mostly it's an alternate for drivers that don't have room to merge over for the left exit to I-10; it also tells drivers in the Mission Rd exit-only lane that they can re-enter either freeway (I-10 or US 101 to I-5/CA 60).  It's just taking the exit and continue straight across the intersection onto the on-ramp (which splits for the two freeways).

Also near downtown LA, I-710 North is marked as "ALT TRUCK ROUTE" since the ramp from I-710 to I-5 North is a left exit and entry (and that part of I-5 can get very congested approaching the East LA Interchange). A later sign clarifies that trucks headed for I-5 North should follow I-710 to I-10 West to I-5 North; trucks headed for US 101 North should take CA-60 West to US 101 North.
Title: Re: Alternate Interstate Highways?
Post by: CardInLex on October 07, 2021, 08:19:47 PM
I'm sure a lot of this has been discussed in the past -- Pennsylvania's color-coded detours, Missouri's "Incident Bypass Route" signage, etc.

Kentucky was looking to sign something in the western part of the state. There's a lot of work being done on I-24, and a lot of truck wrecks in the work zone that caused issues. I found a bunch of examples from Street View (many from Wisconsin and Michigan) to send to my colleague in Paducah for examples.

This should be a national standard, each state having a different signage is confusing.

The proposed new MUTCD standardizes the use of emergency route signing. A new plaque is introduced that says “EMERGENCY ROUTE TO.” Also allows the use of letters to designate routings (I.e. “EMERGENCY ROUTE A.”)
Title: Re: Alternate Interstate Highways?
Post by: vdeane on October 07, 2021, 08:31:54 PM
Los Angeles has a short ALT I-5/I-10/CA 60:  https://goo.gl/maps/MbVe8Cp4WZpCePkR8

Mostly it's an alternate for drivers that don't have room to merge over for the left exit to I-10; it also tells drivers in the Mission Rd exit-only lane that they can re-enter either freeway (I-10 or US 101 to I-5/CA 60).  It's just taking the exit and continue straight across the intersection onto the on-ramp (which splits for the two freeways).

Also near downtown LA, I-710 North is marked as "ALT TRUCK ROUTE" since the ramp from I-710 to I-5 North is a left exit and entry (and that part of I-5 can get very congested approaching the East LA Interchange). A later sign clarifies that trucks headed for I-5 North should follow I-710 to I-10 West to I-5 North; trucks headed for US 101 North should take CA-60 West to US 101 North.
Alternate Truck routes?  Is CalTrans learning from PennDOT?
Title: Re: Alternate Interstate Highways?
Post by: Ned Weasel on October 07, 2021, 09:07:37 PM
The only place I've ever seen this myself is in Kansas City, where I-670 was signed as Alternate I-70. Although looking at street view, this may not be the case anymore?

MODOT did that, but KDOT never did.  I didn't know the Alt I-70 signs were removed, so I guess I haven't driven that way in a while.

Maybe someone thought eight shields on this sign were enough: https://goo.gl/maps/P2XFe3oXM7jVASyD9
Title: Re: Alternate Interstate Highways?
Post by: achilles765 on October 09, 2021, 12:17:30 AM
I do remember that in Louisiana, US 190 from west of Baton Rouge to about US 61 had signs that directed motorists that it was “Incident alternate route interstate 10.”
Title: Re: Alternate Interstate Highways?
Post by: Hot Rod Hootenanny on October 11, 2021, 01:36:03 AM
I do remember that in Louisiana, US 190 from west of Baton Rouge to about US 61 had signs that directed motorists that it was “Incident alternate route interstate 10.”
Those signs went from I-110 to at least LA 415, if not all the way to I-49.
Title: Re: Alternate Interstate Highways?
Post by: jbnv on October 11, 2021, 10:57:34 AM
I do remember that in Louisiana, US 190 from west of Baton Rouge to about US 61 had signs that directed motorists that it was “Incident alternate route interstate 10.”
Those signs went from I-110 to at least LA 415, if not all the way to I-49.

There are signs for “Incident alternate route interstate 10” on I-49 as well.

Speaking of Louisiana, there are also these things posted along US 190 between Baton Rouge and Hammond. They're mounted on rotating polls so they can be "hidden" when not in use. Frankly I think it's a waste of money since I never see them turned to face traffic. DOTD should just sign all of US 190 between BR and Hammond as "EMERGENCY I-12" (or even Business I-12) and be done.

(https://live.staticflickr.com/5483/31285618005_ef06b442e9_w.jpg)
Title: Re: Alternate Interstate Highways?
Post by: vdeane on October 11, 2021, 09:00:22 PM
I-495 in NY has an alternate I-495 signed from the mainline (https://www.google.com/maps/@40.7868287,-73.5280269,3a,75y,251.08h,98.17t/data=!3m6!1e1!3m4!1s0w8MGK1dw2k6HzPeIHLiCw!2e0!7i13312!8i6656).
Title: Re: Alternate Interstate Highways?
Post by: Great Lakes Roads on October 18, 2021, 12:22:22 AM
Indiana uses white on blue "Emergency Detour" signs at certain places along I-65, I-69, and I-469. Fort Wayne and Lafayette are where I have seen them - not sure if there are other ones.

https://www.google.com/maps/@41.1307723,-85.1590783,3a,15y,344.1h,89.3t/data=!3m7!1e1!3m5!1swwTn1Mwhz82lKdtXVE8y7g!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwwTn1Mwhz82lKdtXVE8y7g%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D63.50002%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656 (https://www.google.com/maps/@41.1307723,-85.1590783,3a,15y,344.1h,89.3t/data=!3m7!1e1!3m5!1swwTn1Mwhz82lKdtXVE8y7g!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DwwTn1Mwhz82lKdtXVE8y7g%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D63.50002%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656)

They are also posted on certain places along I-94
Title: Re: Alternate Interstate Highways?
Post by: bing101 on October 18, 2021, 03:14:47 PM
Los Angeles has a short ALT I-5/I-10/CA 60:  https://goo.gl/maps/MbVe8Cp4WZpCePkR8 (https://goo.gl/maps/MbVe8Cp4WZpCePkR8)

Mostly it's an alternate for drivers that don't have room to merge over for the left exit to I-10; it also tells drivers in the Mission Rd exit-only lane that they can re-enter either freeway (I-10 or US 101 to I-5/CA 60).  It's just taking the exit and continue straight across the intersection onto the on-ramp (which splits for the two freeways).

Also near downtown LA, I-710 North is marked as "ALT TRUCK ROUTE" since the ramp from I-710 to I-5 North is a left exit and entry (and that part of I-5 can get very congested approaching the East LA Interchange). A later sign clarifies that trucks headed for I-5 North should follow I-710 to I-10 West to I-5 North; trucks headed for US 101 North should take CA-60 West to US 101 North.
I seen Truck Route for I-5 in the Sylmar area at the Newhall interchange that gets used as an alternate route.
At the south end of the San Joaquin Valley there is also an alternate I-5 for Trucks specifically and that's at the south end of CA-99.
Title: Re: Alternate Interstate Highways?
Post by: fillup420 on October 18, 2021, 04:47:35 PM
There are Alternate I-40 banners along I-87, US-264 and I-95 to get around the long-term I-40 widened projects between the Raleigh Beltline and [now south of] McGees Crossroads.  When they were first installed, you could follow them all the way.  They've been up so long now that I doubt that you could find your way using signs alone.

Did I actually say I-87?   :pan:

You can also find an  "ALT ROUTE" I-40 sign at the end of the off-ramp from I-40 West to US-117 at the interchange between Warsaw and Magnolia (Exit 369). That one's been there long before the Raleigh projects started.

One can also find this head-scratcher (https://www.google.com/maps/@35.630946,-78.5534147,3a,34.4y,108.38h,88.67t/data=!3m6!1e1!3m4!1sO7rOw5Ikv9Rm_PPnPi-Ftw!2e0!7i16384!8i8192) on the US 70 Clayton bypass just east of the jct with I-40
Title: Re: Alternate Interstate Highways?
Post by: oscar on October 18, 2021, 05:37:23 PM
I seen Truck Route for I-5 in the Sylmar area at the Newhall interchange that gets used as an alternate route.
At the south end of the San Joaquin Valley there is also an alternate I-5 for Trucks specifically and that's at the south end of CA-99.

The Newhall truck route is a separate freeway in both directions, with a different centerline from the I-5 mainline, and Caltrans treats it as a separate route (route 5S). It's an old routing that trucks are required to use, to bypass the I-5/I-210/CA 14 mess. Cars can use it too, and indeed use it to exit to the Sierra Highway (historic US 6), which has no exit from the mainline.

The truck lanes at the south end of CA 99 are southbound-only.
Title: Re: Alternate Interstate Highways?
Post by: Evan_Th on October 18, 2021, 09:07:24 PM
There are Alternate I-40 banners along I-87, US-264 and I-95 to get around the long-term I-40 widened projects between the Raleigh Beltline and [now south of] McGees Crossroads.  When they were first installed, you could follow them all the way.  They've been up so long now that I doubt that you could find your way using signs alone.

Did I actually say I-87?   :pan:

You can also find an  "ALT ROUTE" I-40 sign at the end of the off-ramp from I-40 West to US-117 at the interchange between Warsaw and Magnolia (Exit 369). That one's been there long before the Raleigh projects started.

One can also find this head-scratcher (https://www.google.com/maps/@35.630946,-78.5534147,3a,34.4y,108.38h,88.67t/data=!3m6!1e1!3m4!1sO7rOw5Ikv9Rm_PPnPi-Ftw!2e0!7i16384!8i8192) on the US 70 Clayton bypass just east of the jct with I-40

I'm scratching my head trying to think how that could be ALT W 40.  Do they want you to go all the way east to 95 and then back west on 264?  Wouldn't it be faster to take 42 to 50 to west 70, or 42 to 55 to 540?
Title: Re: Alternate Interstate Highways?
Post by: Revive 755 on October 18, 2021, 10:55:36 PM
Illinois has a couple instances of Alt 39/90:
* Along Business 20 in the Belivdere area (https://goo.gl/maps/UpdWkSheMAQCVMbq5)

* Along IL 76 towards Wisconsin (https://goo.gl/maps/Kt7JMU84s2d5QEpf7)

There also used to be Alt 39 signs along IL 251:  Former example near IL 64 (https://goo.gl/maps/eD85mPXS2L1NBFPF7) (the banners orange but I seem to recall these staying up when there was no construction on I-39.


Iowa used to and probably still has some emergency detour signing for some of their interstates:  Former example for I-380 (https://goo.gl/maps/EaizXfPXfy5EVhni7), former example for I-80 (https://goo.gl/maps/R41TnPnagbZnUXcd8)
Title: Re: Alternate Interstate Highways?
Post by: hbelkins on October 19, 2021, 11:45:09 AM
Illinois has a couple instances of Alt 39/90:
* Along Business 20 in the Belivdere area (https://goo.gl/maps/UpdWkSheMAQCVMbq5)

* Along IL 76 towards Wisconsin (https://goo.gl/maps/Kt7JMU84s2d5QEpf7)

There also used to be Alt 39 signs along IL 251:  Former example near IL 64 (https://goo.gl/maps/eD85mPXS2L1NBFPF7) (the banners orange but I seem to recall these staying up when there was no construction on I-39.

But are they flat?
Title: Re: Alternate Interstate Highways?
Post by: Dirt Roads on October 19, 2021, 06:00:18 PM
One can also find this head-scratcher (https://www.google.com/maps/@35.630946,-78.5534147,3a,34.4y,108.38h,88.67t/data=!3m6!1e1!3m4!1sO7rOw5Ikv9Rm_PPnPi-Ftw!2e0!7i16384!8i8192) on the US 70 Clayton bypass just east of the jct with I-40

I'm scratching my head trying to think how that could be ALT W 40.  Do they want you to go all the way east to 95 and then back west on 264?  Wouldn't it be faster to take 42 to 50 to west 70, or 42 to 55 to 540?

I think that NC-42 -to- NC-50 to US-70 West through Garner is already being used by locals as a construction bypass for I-40 and generally worse off.  I've had to use NC-42 -to- NC-55 -to- NC-540 several times (I usually stay on NC-55 all the way to I-40 to avoid the tolls).  I suspect that the main issue is for those folks who are actually going to Raleigh instead of RTP.  They would need to backtrack into Raleigh on I-40 and/or the Beltline.