Considering that both the Interstate and U.S. route systems have business routes, how come the Interstate Highway System doesn't have an official "Alternate" designation like the U.S. route system?
Perhaps if there were such a designation, just as Business Interstates are signed with green shields, Alternate Interstates could be signed with either brown shields, or all red shields.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffc01.deviantart.net%2Ffs71%2Ff%2F2014%2F257%2F8%2F1%2Finterstate_10_alternate_shield__brown__by_pinkjazzx-d7z8tv0.png&hash=2aaf30502930cf404d4117f25bb390b8aa94c61f)(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffc02.deviantart.net%2Ffs71%2Ff%2F2014%2F257%2Fa%2Fd%2Finterstate_10_alternate_shield__red__by_pinkjazzx-d7z8tpv.png&hash=3eabf87be8428fdd77537025d1615dcf7f3bced9)
The Interstates are supposed to be the best and quickest route between points, which defeats the purpose of an alternate route...
Quote from: roadfro on September 15, 2014, 02:37:09 AM
The Interstates are supposed to be the best and quickest route between points, which defeats the purpose of an alternate route...
But what happens when there is an accident/natural disaster/insert calamity here, and the interstate is closed?
Quote from: kj3400 on September 15, 2014, 03:46:21 AM
But what happens when there is an accident/natural disaster/insert calamity here, and the interstate is closed?
Some states have permanent detour signs posted as a bypass of likely trouble areas, and the signs are folded or otherwise hidden when not needed. During a weather event or other emergency, the signs are exposed, giving motorists an easy-to-follow detour around the blockage.
In my view, the problem with "alternate" (of any kind, including US or state routes) is that "ALT" is a vague descriptor. Motorists would probably assume the alternate route is not the preferred route, but even if it's not
preferred, is it a reasonable substitute, or is it a stopgap that's really intended for emergency use only? Is it a way to avoid traffic backups on the congested main route, or is it a scenic option for Sunday sightseers?
At least banners like "truck" , "bypass" , and "business" make it clear what purpose those routes serve in relation to the main road.
Quote from: briantroutman on September 15, 2014, 04:41:05 AM
Quote from: kj3400 on September 15, 2014, 03:46:21 AM
But what happens when there is an accident/natural disaster/insert calamity here, and the interstate is closed?
Is it a way to avoid traffic backups on the congested main route, or is it a scenic option for Sunday sightseers?
Isn't there a 'scenic byway' banner for that latter option? If not, that would be a good idea.
And technically speaking, isn't I-670 in Kansas City also signed as Alternate I-70? I seem to recall that being true once. The one definitive thing I can say about that is that it is the shorter route.
Quote from: DandyDan on September 15, 2014, 06:39:00 AM
And technically speaking, isn't I-670 in Kansas City also signed as Alternate I-70? I seem to recall that being true once. The one definitive thing I can say about that is that it is the shorter route.
It still was back in June.
Yeah. In Ohio, there are Alt I-70 shields that I can only assume are detours from the interstate if it is backed up or closed.
iPhone
There's a section of NY 25 in Jericho, New York, that has some Alternate I-495 signs on it. Not an official designation, I suppose, but the signs are there.
Neither brown nor red is an appropriate color for an interstate shield.
Quote from: dgolub on September 15, 2014, 08:49:17 AM
There's a section of NY 25 in Jericho, New York, that has some Alternate I-495 signs on it. Not an official designation, I suppose, but the signs are there.
I think I remember having seen Alt I-45 signs south of Houston and possibly Alt I-37 signs around Corpus Christi, too. This would have been many years ago; I'm thinking they were supplemented and then supplanted by Hurricane Evacuation Route signs. Anyone else? or was it just a dream.....
This is one thing they do well on Germany's Autobahn system. Between every interchange (wherever possible, and they do their best to make it possible) there is a set of local roads designated with permanent signage that provides an alternate route between the interchanges, in case something blocks the main highway.
Here's some more info: http://www.german-autobahn.eu/index.asp?page=construction
Alternate I-10 shields are posted along US 190 in south Louisiana for relief from the I-10 Atchafalaya Basin Bridge. Some of the "Alternate" banners are blue to match the shield, but some are white. They each have "xx miles" beneath to show the distance back to I-10 which is very helpful. Also on I-49 between US 190 and I-10 the alternate I-10 is shown on a LGS
Quote from: DandyDan on September 15, 2014, 06:39:00 AM
And technically speaking, isn't I-670 in Kansas City also signed as Alternate I-70? I seem to recall that being true once. The one definitive thing I can say about that is that it is the shorter route.
Quote from: Laura on September 15, 2014, 08:31:14 AM
Yeah. In Ohio, there are Alt I-70 shields that I can only assume are detours from the interstate if it is backed up or closed.
iPhone
Well then, on that note, maybe the NJ Turnpike should be signed as ALT I-95 for those who wish to avoid Philadelphia.
Quote from: Pink Jazz on September 15, 2014, 01:32:12 AM
Considering that both the Interstate and U.S. route systems have business routes, how come the Interstate Highway System doesn't have an official "Alternate" designation like the U.S. route system?
Perhaps if there were such a designation, just as Business Interstates are signed with green shields, Alternate Interstates could be signed with either brown shields, or all red shields.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffc01.deviantart.net%2Ffs71%2Ff%2F2014%2F257%2F8%2F1%2Finterstate_10_alternate_shield__brown__by_pinkjazzx-d7z8tv0.png&hash=2aaf30502930cf404d4117f25bb390b8aa94c61f)(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffc02.deviantart.net%2Ffs71%2Ff%2F2014%2F257%2Fa%2Fd%2Finterstate_10_alternate_shield__red__by_pinkjazzx-d7z8tpv.png&hash=3eabf87be8428fdd77537025d1615dcf7f3bced9)
In California if an interstate needs to be closed or renovated in Some cases it will say "Detour" in Orange and interstate shield is colored orange in some cases. Please check with your state.
Quote from: briantroutman on September 15, 2014, 04:41:05 AM
In my view, the problem with "alternate" (of any kind, including US or state routes) is that "ALT" is a vague descriptor. Motorists would probably assume the alternate route is not the preferred route, but even if it's not preferred, is it a reasonable substitute, or is it a stopgap that's really intended for emergency use only? Is it a way to avoid traffic backups on the congested main route, or is it a scenic option for Sunday sightseers?
At least banners like "truck" , "bypass" , and "business" make it clear what purpose those routes serve in relation to the main road.
And then you have the issues with whether a route is signed as Alternate XX or XXA. For US 41, the route is signed "Alternate US 41" in Kentucky but "US 41A" in Tennessee.
In at least one case the signed alternate route is the better route. Between Jonesville and Abingdon, Va., Alternate US 58 is mostly four-lane. Only a couple of short stretches are two-lane roads. "Regular" US 58 is two lanes except for its overlaps with US 23 and I-81.
Don't forget Nebraska and its long "Alternate I-80" route.
Quote from: bing101 on September 15, 2014, 10:48:40 AM
In California if an interstate needs to be closed or renovated in Some cases it will say "Detour" in Orange and interstate shield is colored orange in some cases. Please check with your state.
There IS some informal Alternate interstate signage in the Los Angeles area, but for extremely short distances:
http://goo.gl/maps/ZaRdj
Quote from: hubcity on September 15, 2014, 10:05:25 AM
This is one thing they do well on Germany's Autobahn system. Between every interchange (wherever possible, and they do their best to make it possible) there is a set of local roads designated with permanent signage that provides an alternate route between the interchanges, in case something blocks the main highway.
Here's some more info: http://www.german-autobahn.eu/index.asp?page=construction
Pennsylvania does this with colored detours.
Quote from: NE2 on September 15, 2014, 11:29:39 AM
Quote from: hubcity on September 15, 2014, 10:05:25 AM
This is one thing they do well on Germany's Autobahn system. Between every interchange (wherever possible, and they do their best to make it possible) there is a set of local roads designated with permanent signage that provides an alternate route between the interchanges, in case something blocks the main highway.
Here's some more info: http://www.german-autobahn.eu/index.asp?page=construction
Pennsylvania does this with colored detours.
Baton Rouge has an "Emergency" Alternate I-10 that follows US 190.
Quote from: NE2 on September 15, 2014, 11:29:39 AM
Quote from: hubcity on September 15, 2014, 10:05:25 AM
This is one thing they do well on Germany's Autobahn system. Between every interchange (wherever possible, and they do their best to make it possible) there is a set of local roads designated with permanent signage that provides an alternate route between the interchanges, in case something blocks the main highway.
Here's some more info: http://www.german-autobahn.eu/index.asp?page=construction
Pennsylvania does this with colored detours.
As does Great Britain with its various shapes.
Regarding the general principle of "alternate" Interstate routes, I'd always assumed the numbering system for three-digit routes was intended to serve that function to some degree. If you're approaching Jacksonville and you see the sign for I-295, you know that's an "alternate" to taking I-95 through the city, for example.
Usually when states in which I drive need to post an alternate route for an Interstate, they use either temporary signs (such as those trailer-type message boards) or signs appropriate for the reason the road is closed (such as orange signs for construction). I remember for many years there were orange signs all over the place in the Bay Ridge section of Brooklyn reading "ALT ROUTE TO [I-278 shield] EAST," but I don't remember what project was underway that necessitated them. Probably something to do with the Belt Parkway between Exit 2 and the road's end at the Gowanus, given that Exit 2 for Fourth Avenue was posted with the "ALT ROUTE" banner (indeed it covered up the exit arrow, so a second one was installed further up the sign, and the latter was not removed when the orange banner came down, yielding a weird-looking BGS with two exit arrows). My grandparents lived in Bay Ridge, so I used to see those signs every time we visited.
Steve Anderson has a picture of the weird two-arrow sign. The original arrow is the one on the bottom; it was covered by the orange "ALT ROUTE" banner for what seemed like several years:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.nycroads.com%2Fexits%2Fcross-island_SB_belt_WB%2Fimg10.jpg&hash=570518a360da0e5a06ee40264da697b5eba27e08)
Along I-84 Eastbound in Cheshire, CT near Exit 27 (I-691) (http://goo.gl/maps/6bC5c), there is an ALT I-84 trailblazer signs pointing to the I-691 routing.
You know, I've always thought of suffixed Interstates as "Alternate Interstates," in a sense. The best example I can think of is I-15E (now I-215) in California, as it returns to I-15. Of course, I-80N [now I-84 (W)] and I-15W [now I-86 (W)] may have qualified, but I can understand why they may not.
The thing is that 3dis and the occasional business loop freeway connecting to their associated 2di are what I would consider alternate Interstates. I wouldn't have minded if there were more suffixed Interstates (like I-15E) or even lettered spurs/loops (I-95A, I-95B, etc.)* around today IMO.
*IIRC this was one of the earliest plans for 3dis and even the Interstate system (think I-A, I-B, etc.), correct?
I think it's funny like when you're driving in Wisconsin they have "alternate 94" which is just US highway 51 running alongside it. But it worked out well since there was a traffic jam (51 is two lanes).
Quote from: Rover_0 on September 15, 2014, 03:16:04 PM
*IIRC this was one of the earliest plans for 3dis and even the Interstate system (think I-A, I-B, etc.), correct?
IIRC, I-459 in Alabama was originally submitted as I-59B.
During the Medford (MA) Fast 14 bridge replacement project on I-93 in the summer of 2012, the section of I-95 (OK - 128 for those of you stuck in 1972) between Canton and Woburn was signed as "ALT 93" At most major junctions along I-95, they had large white on green signs indicating "ALT 93 SOUTH (NORTH) with appropriate directional arrows. At other locations between interchanges, they had confirmatory markers.
ALT I-35/35E/35W signage exists around Hillsboro, Texas, due to the presence of the split.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fi1209.photobucket.com%2Falbums%2Fcc395%2FBrian5561%2F07022011slr144.jpg&hash=766399818cbdda107929798fbd6ed8d4d1bef906) (http://s1209.photobucket.com/user/Brian5561/media/07022011slr144.jpg.html)
Quote from: Brian556 on September 15, 2014, 07:53:56 PM
ALT I-35/35E/35W signage exists around Hillsboro, Texas, due to the presence of the split.
Are those still posted? Thought those were temporary while 35 was widened. No real point to them anymore with the 3 segments around Hillsboro having been finished by mid-2012.
Quote from: dfwmapper on September 16, 2014, 02:55:08 AM
Quote from: Brian556 on September 15, 2014, 07:53:56 PM
ALT I-35/35E/35W signage exists around Hillsboro, Texas, due to the presence of the split.
Are those still posted? Thought those were temporary while 35 was widened. No real point to them anymore with the 3 segments around Hillsboro having been finished by mid-2012.
They're still signed, but the signage is strange. Alt I-35E and Alt I-35W are signed going northbound from SH 81 and SS 579, while the same routes are signed Alt I-35 going southbound. SH 81 southbound is signed as Alt I-35 to some point, presumably the northern intersection with SH 22/171, where To South I-35 signage begins. There is what appears to be a separate Alt I-35 going north along SH 81 from the I-35 split. This route is signed north along SH 81 until it splits into Alt I-35E and Alt I-35W at SS 579. The signage seems haphazard, which is uncharacteristic for TxDOT, which is usually pretty meticulous about signage (much to my appreciation).
Quote from: Rover_0 on September 15, 2014, 03:16:04 PM
You know, I've always thought of suffixed Interstates as "Alternate Interstates," in a sense. The best example I can think of is I-15E (now I-215) in California, as it returns to I-15. Of course, I-80N [now I-84 (W)] and I-15W [now I-86 (W)] may have qualified, but I can understand why they may not.
The thing is that 3dis and the occasional business loop freeway connecting to their associated 2di are what I would consider alternate Interstates. I wouldn't have minded if there were more suffixed Interstates (like I-15E) or even lettered spurs/loops (I-95A, I-95B, etc.)* around today IMO.
*IIRC this was one of the earliest plans for 3dis and even the Interstate system (think I-A, I-B, etc.), correct?
What about I-5w in Oakland on US-50 now I-580 does this count.
Quote from: bing101 on September 16, 2014, 10:49:24 AM
Quote from: Rover_0 on September 15, 2014, 03:16:04 PM
You know, I've always thought of suffixed Interstates as "Alternate Interstates," in a sense. The best example I can think of is I-15E (now I-215) in California, as it returns to I-15. Of course, I-80N [now I-84 (W)] and I-15W [now I-86 (W)] may have qualified, but I can understand why they may not.
The thing is that 3dis and the occasional business loop freeway connecting to their associated 2di are what I would consider alternate Interstates nowadays. I wouldn't have minded if there were more suffixed Interstates (like I-15E) or even lettered spurs/loops (I-95A, I-95B, etc.)* around today IMO.
*IIRC this was one of the earliest plans for 3dis and even the Interstate system (think I-A, I-B, etc.), correct?
What about I-5w in Oakland on US-50 now I-580 does this count.
Yes.
Added the bolded word for clarification.
To me, the Nebraska method is the best for permanently signed detours- it's a one piece sign that clearly indicates the purpose, far better than an ALT banner over a full sized shield
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.corcohighways.org%2Fhighways%2Fne%2F30%2Fl53atol17b%2F3.JPG&hash=996b20e949efebb0c7574f50fad18268cd9b0677)
Quote from: corco on September 18, 2014, 12:10:02 AM
To me, the Nebraska method is the best for permanently signed detours- it's a one piece sign that clearly indicates the purpose, far better than an ALT banner over a full sized shield
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwww.corcohighways.org%2Fhighways%2Fne%2F30%2Fl53atol17b%2F3.JPG&hash=996b20e949efebb0c7574f50fad18268cd9b0677)
I must be missing something...Nebraska adds the word "Route" and a cardinal direction to what otherwise looks like a regulatory sign. What makes that better than a regular route marker with an Alternate banner (https://www.google.com/maps?ll=43.200171,-89.323654&spn=0.00025,0.222988&t=m&z=13&layer=c&cbll=43.200699,-89.323504&panoid=7GQcA_qsRfEVu6Em-ESPkQ&cbp=12,33.07,,1,3.08)?
It's more clearly differentiated from a route a person might want to travel on purpose. As a route that functionally is used only as a detour, it shouldn't be signed like a normal alternate route.
To me an alt would be a 3di..i with an even first number, since to me that means bypass, or alt route around a place.
Quote from: corco on September 18, 2014, 09:40:11 AM
It's more clearly differentiated from a route a person might want to travel on purpose. As a route that functionally is used only as a detour, it shouldn't be signed like a normal alternate route.
It should be signed instead like normal alternate routes used to be? (I think - I know I've seen BUSINESS / ROUTE plates)
I like PennDOT's practice the most. The use of a colored arrow as opposed to a bannered alternate route number mitigates confusion about what the best route would normally be. However, when there's a specific event that demands usage of an alternate route (e.g., construction, accident, inclement weather), the arrows are in place to guide traffic onward.