Alternate routes for Interstate crossings

[mcdonaat]

I was told yesterday by the LaDOTD that all interstate routes must have an alternate route available for motorists if a bridge collapses or some other event. It's the first I've heard about this, especially with I-20 at Vicksburg and I-10 at Orange, Tx having no alternate crossings. Any opinions?

[bugo]

Sounds like the employee who told you that didn't know what they were talking about. 

Another example is I-10 through the swamps.  There is no alternative to that highway.  Sure you can take US 90 or 190 but they are way out of the way and could not be considered true alternatives.

[mcdonaat]

Sounds like the employee who told you that didn't know what they were talking about. 

Another example is I-10 through the swamps.  There is no alternative to that highway.  Sure you can take US 90 or 190 but they are way out of the way and could not be considered true alternatives.

Tell that to the guys who have posted "Alternate Route I-10" on US 190.

Technically, you have US 90 too, with 70MPH stretches.

[national highway 1]

I-70 in Utah, 110mi between services.

[cpzilliacus]

I was told yesterday by the LaDOTD that all interstate routes must have an alternate route available for motorists if a bridge collapses or some other event. It's the first I've heard about this, especially with I-20 at Vicksburg and I-10 at Orange, Tx having no alternate crossings. Any opinions?

I-95 across Lake Marion north of Santee, South Carolina (Orangeburg and Clarendon Counties) has no nearby alternatives.  The "alternate" routes, U.S. 301 and U.S. 15, are all multiplexed onto I-95 to cross the lake (the center part of the former structure crossing the lake was removed when I-95 was built and now serves as two fishing piers). 

Downstream, the only through parallel routes are U.S. 52 and U.S. 17, upstream a combination of U.S. 78 or U.S. 378 and U.S. 601 and I-26 (all of these representing a considerable detour).  I have personally driven U.S. 52 from Florence to Charleston, and it's not a bad road, but it does not have the capacity to serve as a substitute for I-95.

[agentsteel53]

Technically, you have US 90 too, with 70MPH stretches.

in Louisiana?  I don't recall such a segment.  could you please name one?  is it fully limited-access?

[vdeane]

I-81 between NY 12 (exit 50) and Island Road (exit 51) over the Thousand Islands Bridge; closest routes to Canada are the Ogdensburg-Prescott International Bridge and the Wolfe Island Ferry - neither of which help if you're trying to get to the island state parks.

[Mapmikey]

I-95 across Lake Marion north of Santee, South Carolina (Orangeburg and Clarendon Counties) has no nearby alternatives.  The "alternate" routes, U.S. 301 and U.S. 15, are all multiplexed onto I-95 to cross the lake (the center part of the former structure crossing the lake was removed when I-95 was built and now serves as two fishing piers). 

US 15-301 was still on its own Lake Marion bridge until about 1987.  I-95 was constructed here in the late 60s.

I would guess the alleged requirement is not absolute otherwise more states would post these alternative routings like Pennsylvania does.  Obviously some interstate segments cannot easily comply with ths idea, but I don't think close proximity is necessarily an overriding factor.  The West Virginia Turnpike has Emergency Routes posted on roads that stray quite far from the turnpike, such as US 19 at I-79.

Mapmikey

[kphoger]

The comment sounds to me like every segment of Interstate highway must have some other highway designated as an alternate–not that an Interstate wouldn't be built if there weren't an alternate conveniently nearby.  So, while some of the examples above might not have nice wide highway in proximity, that doesn't mean those far-away highways wouldn't still be officially designated as alternate routes.

[mcdonaat]

Technically, you have US 90 too, with 70MPH stretches.

in Louisiana?  I don't recall such a segment.  could you please name one?  is it fully limited-access?

An example is between Morgan City and Houma. It's 70MPH, controlled-access, and a lot of US 90 is elevated.

[mcdonaat]

The main idea is that the crossings have nearby alternative crossings that motorists can take. The Atchafalaya on I-10 has US 90 and US 190, both four lane highways. I-10 twin spans have US 11 and US 90. I-55 over Pass Manchac has old US 51, and I-10 over the Calcasieu has I-220. Each major river crossing should have an alternate route for local traffic, while the main gist of traffic can be diverted along other routes. The only exceptions are on state lines, with I-59 at MS, I-20 at MS, and I-10 at TX being the lone exceptions.

[sandwalk]

There are signs throughout the Rockford, IL region for ALT I-39/90.  These are generally on 2-lane, state highways, such as IL-251 and IL-76.

[The High Plains Traveler]

There is no state highway alternate to I-25 between Pueblo and Colorado Springs, without driving about 20 miles, or 50% further, out of the way. There isn't even a continuous paved frontage road, since much of the original U.S. 85/87 was converted directly into one carriageway of the interstate over 50 years ago.

[sp_redelectric]

Quick, someone tell the CRC planners in Portland, Oregon/Vancouver, Washington!

(OK, so I-205 exists since 1982 or whenever the Glenn Jackson was built, but the nearest alternates are SR 432/Lewis & Clark Bridge connecting Rainier with Longview (about 40 miles north), or the Bridge of the Gods (about 40 miles east, closed to commercial traffic) or Hood River bridges (about 60 miles east).

And I-82 is even worse - requring a long trek out U.S. 730 to 12 back to the Tri-Cities, or U.S. 97 at Biggs Junction (about 70 miles west).

[NE2]

It would be nice if there were a law requiring either a reasonable alternate for all vehicles and peds or allowing them on the Interstate, but no such luck.

[mcdonaat]

It would be nice if there were a law requiring either a reasonable alternate for all vehicles and peds or allowing them on the Interstate, but no such luck.

At least force builders to incorporate separate bike paths on the bridges.

[nwi_navigator_1181]

After the flood of 2008, an emergency detour for I-(80/)94 (80 is in parentheses because it is not mentioned in signage) was shoehorned onto U.S. 30, and then was later moved north onto U.S. 20 after I-65 reopened for reconstruction. It was one of those instances where a route was in place after the fact.

Worse, the signs are so scattered that one may not know how to traverse this route. I can somewhat connect the dots and determine that Indiana's emergency route is to connect to Michigan's Emergency I-94 route via Indiana 212 in Michigan City. Heading westbound, I really have no clue.

[Anthony_JK]

Sounds like the employee who told you that didn't know what they were talking about. 

Another example is I-10 through the swamps.  There is no alternative to that highway.  Sure you can take US 90 or 190 but they are way out of the way and could not be considered true alternatives.

It's not THAT far out of the way...20 miles on I-49 to Opelousas, 50 miles on US 190 to the LA 415 interchange, and 4 miles back to I-10. Or..continue on US 190 across the old Miss. River bridge to Airline Highway. And, it's continuous 4-lane all the way through (the speed traps in Port Barre, Krotz Springs, and Livonia aside, of course).

[bugo]

It's a long detour if you're going from say Henderson to Ramah.

[mcdonaat]

Sounds like the employee who told you that didn't know what they were talking about. 

Another example is I-10 through the swamps.  There is no alternative to that highway.  Sure you can take US 90 or 190 but they are way out of the way and could not be considered true alternatives.

It's not THAT far out of the way...20 miles on I-49 to Opelousas, 50 miles on US 190 to the LA 415 interchange, and 4 miles back to I-10. Or..continue on US 190 across the old Miss. River bridge to Airline Highway. And, it's continuous 4-lane all the way through (the speed traps in Port Barre, Krotz Springs, and Livonia aside, of course).

Who goes to Ramah? if you have every intent of going to Ramah as a destination, you probably own a boat.

[huskeroadgeek]

In Nebraska, US 34 and US 30 and the roads that connect them to I-80 are marked with "Alternate I-80" signs. I see mention above of similar signs for I-10 on US 190 in Louisiana and for I-39/I-90 in Rockford, IL-how many other places have permanent signs designating alternate interstate routes?

[bulldog1979]

I was told yesterday by the LaDOTD that all interstate routes must have an alternate route available for motorists if a bridge collapses or some other event. It's the first I've heard about this, especially with I-20 at Vicksburg and I-10 at Orange, Tx having no alternate crossings. Any opinions?

Well if this were the case, I-75 in Michigan has an issue should anything ever happen to the Mackinac Bridge. That five-mile crossing over the Straits of Mackinac would turn into a 860-mile detour through Chicago or 563 miles if it's during the summer and the SS Badger is an option across Lake Michigan

[bugo]

Signing alternate Interstates is a pretty good idea and more states should look into it.

[mcdonaat]

I'll post a photo tomorrow afternoon, but usually the LaDOTD posts Alt. Route I-10. However, the blue Alternate shields are even showing up, making US 190 a true alternate route. Wouldn't be surprised to see US 90 posted soon

[jdb1234]

I remember there being Alternate I-77 signs on OH 21 near Akron when I was up there in 2006.  I wonder if they are still there.