Interstate one lane mainlines

Alex · January 30, 2009, 01:12:58 PM

Interstate 10 travelers are relegated to one through lane at the interchange where the route merges with Interstate 35 southwest of downtown San Antonio:

http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=nwzh5v6sqndr&style=b&lvl=1&tilt=-90&dir=0&alt=-1000&scene=6114579&phx=0&phy=0&phscl=1&encType=1

Additionally Interstate 278 drivers are relegated to one through lane when the route switches from the BQE to the GCP in Brooklyn:

http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=qsv4y88v74bf&style=b&lvl=1&tilt=-90&dir=0&alt=-1000&scene=1769140&phx=0&phy=0&phscl=1&encType=1

How many others are there?

FLRoads · January 30, 2009, 01:28:05 PM

To stay on Interstate 84 eastbound at the interchange with Interstate 86 in Idaho, travelers are regulated to one through lane.

http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=42.569936~-113.517673&style=h&lvl=16&tilt=-90&dir=0&alt=-1000&phx=0&phy=0&phscl=1&encType=1

okroads · January 30, 2009, 01:35:09 PM

There are several of these in the Oklahoma City area:

There is only one lane on either direction of I-35 through the I-35/I-235/I-40 interchange.

I-44 East exits off the mainline freeway on one lane at the OK 3/OK 66/OK 74 interchange in northwest OKC.

I-44 through traffic is one lane only in both directions where it leaves/enters the Turner Turnpike.

akotchi · January 30, 2009, 01:39:33 PM

I-93 is one lane each direction for a few miles through the Franconia Notch Park in norther New Hampshire.

I-278 also reduces to one lane each way through the NJ Turnpike interchange.

This seems like a pretty common occurrence at the ends of (some) multiplexes and at major interchanges involving multiple interstate highways, especially when one changes direction at the interchange.

mefailenglish · January 30, 2009, 01:59:50 PM

As I recall I-40 eastbound shrinks to one lane on a ramp at the interchange with I-240 on the east side of Memphis.

Bryant5493 · January 30, 2009, 02:17:18 PM

I-20 in west Georgia was one lane in either direction (east and west), while the freeway pavement (concrete) was being rehabilitated.

Be well,

Bryant

Revive 755 · January 30, 2009, 02:47:16 PM

Voyager · January 30, 2009, 03:06:20 PM

I-5 does this when it exits off of itself in two different places in the central valley.

PAHighways · January 30, 2009, 03:24:56 PM

I-83 northbound at PA 581 in Harrisburg

I-279 at I-376 used to be one lane going south onto the Fort Pitt Bridge before the bridge and tunnel reconstruction.

vdeane · January 30, 2009, 04:01:41 PM

I-81 over the Thousands Islands Bridge is only one lane each direction. And no median, either; just a double yellow line. You can't even tell it's an interstate, especially since NYSDOT refuses to sign it as such on guide signs.

djracer201 · January 30, 2009, 04:16:32 PM

I-185 at its north end near LaGrange, GA - the ramp to I-85 SB is one lane for 1/4 Mile - Looks like a stub end as well with enough room for 2 lanes.

TheHighwayMan3561 · January 30, 2009, 04:23:37 PM

I-394 WB in Minneapolis drops to one lane after the exit to the HOV reversible lanes. It gains 2 more from the I-94 West on-ramp quickly after (about 1/4 mile), though.

Duke87 · January 30, 2009, 05:53:11 PM

I-70 at I-695.

And need I mention the crazy situation where Ohio Turnpike exit 218 involves ramps such that you briefly have one lane that's both I-76 east and I-80 west (and vice versa)?

agentsteel53 · January 30, 2009, 05:57:46 PM

I-8 about a mile from its beginning in San Diego. At the I-5 junction, it reduces to one lane temporarily.

I-95 at the infamous cloverleaf in Canton where it is routed onto beltway 128 because, hey look at that, they forgot to build it going forward.

then again, it reduces to zero lanes in New Jersey, which is even sillier.

mightyace · January 30, 2009, 06:03:12 PM

Quote from: Duke87 on January 30, 2009, 05:53:11 PM
And need I mention the crazy situation where Ohio Turnpike exit 218 involves ramps such that you briefly have one lane that's both I-76 east and I-80 west (and vice versa)?

I commented about that interchange in another forum talking about numbers changing while remaining on the physical road's mainline.

Not, only do you have that, but they also reactivated and reconnected part of the ORIGINAL interchange 15 (old numbering) to restore access to county highway 18 (former Ohio 18). Man that extension is goofy!

Revive 755 · January 30, 2009, 06:43:34 PM

Also both ways on I-83 at the strange I-283/US 322 interchange:
http://maps.google.com/maps?hl=en&ie=UTF8&ll=40.253304,-76.811857&spn=0.003767,0.010986&t=k&z=17

algorerhythms · February 01, 2009, 02:28:50 PM

I-79 at I-70 in Washington, PA

Urban Prairie Schooner · February 03, 2009, 09:30:46 PM

I-10 EB at I-110, as you come off the Miss. River bridge in Baton Rouge:

http://www.southeastroads.com/louisiana001/i-010_eb_exit_155b_01.jpg (Approaching the I-110 interchange)
http://www.southeastroads.com/louisiana001/i-010_eb_exit_156a_01.jpg (Manuevering on the mainline thru the interchange proper)
http://www.southeastroads.com/louisiana001/i-010_eb_exit_156a_02.jpg (Immediately after the merge with SB 110)

The (virtually 90 degree) ramp to follow I-10 east through the I-110 jct is two lanes wide, but the right lane immediately becomes exit only for Washington Street. So functionally, if not technically, I-10 EB is a one lane mainline at this location.

Gotta love early 1960s interchange design.

Alex · February 03, 2009, 11:33:37 PM

Quote from: Urban Prairie Schooner on February 03, 2009, 09:30:46 PM
I-10 EB at I-110, as you come off the Miss. River bridge in Baton Rouge:

The (virtually 90 degree) ramp to follow I-10 east through the I-110 jct is two lanes wide, but the right lane immediately becomes exit only for Washington Street. So functionally, if not technically, I-10 EB is a one lane mainline at this location.

Gotta love early 1960s interchange design.

Technically speaking, Interstate 10 eastbound at Interstate 65 forces drivers into one lane as one lane ends at the merge with the southbound ramp from Interstate 65, followed by the second lane from the right defaulting to Alabama 163 (Dauphin Island Parkway). All the while travelers must deal with the influx of traffic from the left emanating from Interstate 65.

Anthony_JK · February 04, 2009, 07:54:07 PM

Quote from: Urban Prairie Schooner on February 03, 2009, 09:30:46 PM
I-10 EB at I-110, as you come off the Miss. River bridge in Baton Rouge:

http://www.southeastroads.com/louisiana001/i-010_eb_exit_155b_01.jpg (Approaching the I-110 interchange)
http://www.southeastroads.com/louisiana001/i-010_eb_exit_156a_01.jpg (Manuevering on the mainline thru the interchange proper)
http://www.southeastroads.com/louisiana001/i-010_eb_exit_156a_02.jpg (Immediately after the merge with SB 110)

The (virtually 90 degree) ramp to follow I-10 east through the I-110 jct is two lanes wide, but the right lane immediately becomes exit only for Washington Street. So functionally, if not technically, I-10 EB is a one lane mainline at this location.

Gotta love early 1960s interchange design.

Now, if I remember my history right, the reason for that SNAFU of an interchange design was that in the 1960's when Interstate 10 was in the design stage, it was assumed to use the US 190 corridor through Opelousas and Airline Highway rather than the US 90 corridor; and that the proposed freeway that ultimately became I-110/I-10 was to be a through freeway that would funnel traffic between Scenic Highway and Perkins Road. Apparently, the designers of that time didn't think about the fact that I-10 might be built further south.....thusly, the through movements were assumed to be north-south.

LaDOTD has attempted to jerry-rig a temporary solution recently by shifting some lane usage at the I-10/I-110 Split interchange so that the "off ramp" carrying eastbound I-10 at least merges into two lanes rather than becomes the Washington St. auxilliary ramp. It's helped somewhat....but is no replacement for ultimately building a two-lane ramp.

Personally, I'd totally junk this old model and completely rebuild the interchange so that I-10 gets the through traffic movements and three lanes consistently through it, and that the off-ramp connectors to and from I-110 are two lanes each. That would completely foul up rush hour traffic in BR, though (especially since this thoroughfare is basically BR's only main entry/exit from downtown and the Capitol complex south), so I wouldn't count on that happening.

Also, as part of the widening of I-10 that has been proposed, there was thought of eliminating the Washington St. exit entirely in order to make the "on ramp" more of a through lane and extending a new aux lane from Louisa St. to Dalrymple Drive (first exit that serves LSU and University Lake. Problem was, that exit serves a mostly poor, Black community, and local leaders cried serious foul over losing an exit, even though they could have used other locations such as Highland Road/Nicholson Drive and Louisa St. to access I-10 easily within the existing street system. After the sticker shock of how much a outer toll loop would cost, however, the opinions of those folk has changed a bit; a new study for widening I-10 within BR is now in the works starting this year.

Just a bit of local background.

Anthony

Hellfighter · February 04, 2009, 08:07:09 PM

I-75 at the I-375/M-3 connector in downtown detroit

Alex · February 05, 2009, 10:48:28 AM

Quote from: froggie on February 04, 2009, 06:29:57 PM
QuoteTechnically speaking, Interstate 10 eastbound at Interstate 65 forces drivers into one lane as one lane ends at the merge with the southbound ramp from Interstate 65, followed by the second lane from the right defaulting to Alabama 163 (Dauphin Island Parkway). All the while travelers must deal with the influx of traffic from the left emanating from Interstate 65.

However, since you still have those two lanes between the merge from 65 and the off-ramp to 163, it's not a true "one-lane" situation. Sure you have to merge over, but there's numerous places across the country where that's the case.

No its not, I was drawing the comparison between the Interstate 10/110 configuration in Baton Rouge. Perhaps my use of the term technically speaking was ill-advised.

Michael · February 05, 2009, 01:05:28 PM

Quote from: mightyace on January 30, 2009, 06:03:12 PM
Quote from: Duke87 on January 30, 2009, 05:53:11 PM
And need I mention the crazy situation where Ohio Turnpike exit 218 involves ramps such that you briefly have one lane that's both I-76 east and I-80 west (and vice versa)?

I commented about that interchange in another forum talking about numbers changing while remaining on the physical road's mainline.

Not, only do you have that, but they also reactivated and reconnected part of the ORIGINAL interchange 15 (old numbering) to restore access to county highway 18 (former Ohio 18). Man that extension is goofy!

That is one odd interchange. Here's a link in Microsoft Virtual Earth:
http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=41.112517~-80.836995&style=r&lvl=15&tilt=-90&dir=0&alt=-1000&scene=24526053&phx=0&phy=0&phscl=1&encType=1

Click "Bird's Eye" to see it in detail.

mightyace · February 05, 2009, 01:27:25 PM

Quote from: Michael on February 05, 2009, 01:05:28 PM
Quote from: mightyace on January 30, 2009, 06:03:12 PM
Quote from: Duke87 on January 30, 2009, 05:53:11 PM
And need I mention the crazy situation where Ohio Turnpike exit 218 involves ramps such that you briefly have one lane that's both I-76 east and I-80 west (and vice versa)?

I commented about that interchange in another forum talking about numbers changing while remaining on the physical road's mainline.

Not, only do you have that, but they also reactivated and reconnected part of the ORIGINAL interchange 15 (old numbering) to restore access to county highway 18 (former Ohio 18). Man that extension is goofy!

That is one odd interchange. Here's a link in Microsoft Virtual Earth:
http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=41.112517~-80.836995&style=r&lvl=15&tilt=-90&dir=0&alt=-1000&scene=24526053&phx=0&phy=0&phscl=1&encType=1

Click "Bird's Eye" to see it in detail.

I've been through that interchange dozens of times in my life. From road level it really looked weird when they added the connection to the old exit 15 trumpet on CR 18. I've been on nearly all the ramps at this exit except those to connect with the old exit.

And, if you look closely, you'll see that the extension to the old exit only connects to the turnpike mainline. You can't get to/from the I-76 West/I-80 East free mainline from CR-18 here. However, as CR-18 parallels the freeway, there are other exits to do that.

What I've always wondered is WHY did they do through the trouble to do this? I didn't think that CR-18 had that much traffic.

DrZoidberg · February 05, 2009, 04:26:25 PM

I want to say there are parts of I-90 in western Montana that are 1 lane and only seperated by a double yellow line, but it's been a long time.

News:

Interstate one lane mainlines