One-lane, two-way roads, bridges, and tunnels

[Finrod]

There can't be many significant one-lane two-way roads, bridges, or tunnels in the US; I can think of one of each.

For roads, there's the famous Road to Hana on the island of Maui in Hawaii, where there just isn't enough room to make a two-lane road in some stretches, so it becomes one lane only there-- including around some blind corners, as well as a number of short one-lane bridges.

For bridges (of significant length, there are a lot of short one-lane bridges), there's the Indiana SR 225 bridge over the Wabash River north of Lafayette, where access to the bridge is controlled by sensor-driven stoplights at either end: https://www.google.com/maps/@40.4964222,-86.8244781,3a,75y,132.93h,87.1t/data=!3m6!1e1!3m4!1srODHUiFANVMdnctNUlbf2Q!2e0!7i3328!8i1664

For tunnels, there's the 2.5 mile one-lane tunnel to Whittier, Alaska where the stoplight for it changes every half an hour; it's also a rail tunnel!  https://www.alaska.org/detail/whittier-tunnel

[Max Rockatansky]

Dime a dozen out here, or least I try to find them:

https://www.gribblenation.org/2021/04/mosquito-road-bridge.html?m=1

https://www.gribblenation.org/2019/09/italian-bar-road-road-225-east-through.html?m=1

https://www.gribblenation.org/2018/06/the-sierran-death-highway-blackrock-road.html?m=1

[index]

These ones are somewhat well known, at least among roadgeeks:

https://www.google.com/maps/@39.5333054,-74.3209377,3a,75y,158.3h,86t/data=!3m7!1e1!3m5!1sQ_MNyqa18Oc3AtMW3Bf6hQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DQ_MNyqa18Oc3AtMW3Bf6hQ%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D12.033456%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

https://www.google.com/maps/@39.5202429,-74.3191274,3a,75y,193h,86.31t/data=!3m7!1e1!3m5!1sFzF55t1U56LViTirXiDOaw!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fpanoid%3DFzF55t1U56LViTirXiDOaw%26cb_client%3Dmaps_sv.tactile.gps%26w%3D203%26h%3D100%26yaw%3D65.94073%26pitch%3D0%26thumbfov%3D100!7i16384!8i8192

One-lane bridges and tunnels although not >everywhere< certainly aren't uncommon. The thread would probably be more interesting if those were excluded and it was just one-lane two-way roads. This one at the DE Water Gap comes to mind:

https://www.google.com/maps/@40.9762413,-75.1347626,3a,32.7y,364.11h,92.9t/data=!3m6!1e1!3m4!1s9zgh0KadgMV9Vn7BHVXtyw!2e0!7i16384!8i8192

[SkyPesos]

I thought one lane two way roads/bridges/tunnels are somewhat common, as it was taught in my driving school, while HOV lanes and FYAs weren't mentioned at all.

[ilpt4u]

Wabash Cannonball Bridge between St Francisville, IL and just SW of Vincennes, IN
https://historicbridges.org/bridges/browser/?bridgebrowser=indiana/wabashcannonball/

[Max Rockatansky]

This might be a more exclusive thread if we change this to one lane/two way bridges on Signed Highways.  There are still examples but they are going to be far more rare. 

CA 49 Jersey Bridge

https://flic.kr/p/295jbCY

CA 192 Sycamore Creek Bridge

https://flic.kr/p/2gZFXzz

[hbelkins]

Quite a few one-lane bridges on Kentucky's state-numbered highway system. And there's the Nada Tunnel, the old narrow-guage railroad tunnel now converted to vehicle use on KY 77 in Powell County.

In short succession, KY 1571 in Estill County goes through a one-lane railroad underpass and then across a one-lane bridge.

West Virginia has the Dingess Tunnel on CR 3/5 in Mingo County.

I can think of two one-lane bridges on the US highway system that have been replaced. The first one I encountered was on US 62 in northeastern Kentucky (Mason County, I think, but it may have been Robertson County). And there was one on US 220 somewhere in eastern West Virginia that has been replaced.

[NWI_Irish96]

IN 225 over the Wabash River:

https://www.google.com/maps/@40.4948371,-86.82228,3a,75y,315.63h,84.91t/data=!3m6!1e1!3m4!1s_Ky7qq7fNRSC6aILdlvdYA!2e0!7i3328!8i1664

[Finrod]

Wabash Cannonball Bridge between St Francisville, IL and just SW of Vincennes, IN
https://historicbridges.org/bridges/browser/?bridgebrowser=indiana/wabashcannonball/

Wow, that's a very long one-lane bridge to have no traffic control at all on it.

[FreewayDan]

Carson Street in Long Beach goes under I-710 via a one-way tunnel, but only to a storage business:
https://goo.gl/maps/CschQ4Ci8eUjNq5q7

[Flint1979]

Quite a few one-lane bridges on Kentucky's state-numbered highway system. And there's the Nada Tunnel, the old narrow-guage railroad tunnel now converted to vehicle use on KY 77 in Powell County.

In short succession, KY 1571 in Estill County goes through a one-lane railroad underpass and then across a one-lane bridge.

West Virginia has the Dingess Tunnel on CR 3/5 in Mingo County.

I can think of two one-lane bridges on the US highway system that have been replaced. The first one I encountered was on US 62 in northeastern Kentucky (Mason County, I think, but it may have been Robertson County). And there was one on US 220 somewhere in eastern West Virginia that has been replaced.

The Nada Tunnel is the first one that comes to mind when asked a question like this.

[ozarkman417]

Despite being of the more trafficked roads in Iceland (in a country like Iceland, that isn't saying much, though Route 1 is an important road for tourists), more than half of Route 1's bridges are one-laned, two ways. A few have been upgraded in recent years based on satellite imagery, but they were very plentiful when I was there in June 2018.

[Rick1962]

Layton Bridge and Tunnel east of Perryopolis, PA. Old rail line converted to county road.

SM-T580

[ErmineNotyours]

When I ordered an Uber from Great Falls to Bethesda, MD; I was surprised to find myself on The Cabin John Aqueduct Bridge.

[jay8g]

Washington has at least one on a state route: the SR 503 Yale Bridge over the Lewis River.

As someone already mentioned, one-lane bridges are fairly common in Iceland. But even there, you don't see all that many one-lane tunnels. Here's one in the north end of the country, which is 800 meters long according to the sign, and has absolutely no traffic control to stop people from encountering oncoming traffic in the middle of the tunnel. And there are no passing places, either, and you can't see from one end to the other, so you could end up backing out a long way.

[Bitmapped]

I can think of two one-lane bridges on the US highway system that have been replaced. The first one I encountered was on US 62 in northeastern Kentucky (Mason County, I think, but it may have been Robertson County). And there was one on US 220 somewhere in eastern West Virginia that has been replaced.

The US 220 bridge was over the South Branch Potomac River at Upper Tract, WV. The old bridge was abandoned in place when the new one was built in the mid-2000s. It was still there as of two years ago. https://goo.gl/maps/N5VpJ7oUE6t2RFPc6

US 250 also had a one-lane truss over Pennsylvania Fork Fish Creek south of Cameron, WV. It was replaced about a decade ago, with the original bridge being demolished. GMSV still has the old bridge here: https://goo.gl/maps/xhrBdv4zWaE2jhcUA

[kphoger]

This might be a more exclusive thread if we change this to one lane/two way bridges on Signed Highways.  There are still examples but they are going to be far more rare. 

AR-187, of course.

I used to know some on Missouri secondary state highways, but it appears those bridges have all been replaced with two-lane bridges since I lived in the area.

[index]

https://www.google.com/maps/@35.6237062,-79.1994132,3a,60y,342h,88.63t/data=!3m6!1e1!3m4!1s1wxE2Dr7xIo_OA7GYnDAhg!2e0!7i13312!8i6656

This one-lane bridge in NC is one of the last of its kind in the state you can still drive on. There's another similar one in Wilmington.

This might be a more exclusive thread if we change this to one lane/two way bridges on Signed Highways.  There are still examples but they are going to be far more rare. 

NC 90's unpaved segment has some one-lane bridges:

https://www.google.com/maps/place/35%C2%B059'53.2%22N+81%C2%B046'06.6%22W/@35.9981041,-81.7690542,327m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x0!7e2!8m2!3d35.9981034!4d-81.7685068

https://www.google.com/maps/place/35%C2%B059'24.6%22N+81%C2%B045'46.8%22W/@35.9901621,-81.7635342,327m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x0!7e2!8m2!3d35.9901605!4d-81.7629873

I don't know if any other NC highways have one-lane bridges.

[Max Rockatansky]

Speaking of dirt State Highways AZ 88 had several and if I recall correctly AZ 288 had one over the Salt River.

[kphoger]

Speaking of dirt State Highways AZ 88 had several and if I recall correctly AZ 288 had one over the Salt River.

https://goo.gl/maps/EhefeCbrfBHsj6dq5

[Max Rockatansky]

Speaking of dirt State Highways AZ 88 had several and if I recall correctly AZ 288 had one over the Salt River.

https://goo.gl/maps/EhefeCbrfBHsj6dq5

Yes, that's the one.  Here is a link to the bridgehunter feature on the span:

http://bridgehunter.com/az/gila/37/

I have photos of the two one lane truss spans on AZ 88 but I can't link them from Flickr for some reason at the moment.

[RobbieL2415]

This keystone tunnel runs underneath what used to be a branch of the NYNHH railroad. It's at lease 150 years old and obviously predates the automobile given how narrow it is.
https://www.google.com/maps/@41.8245566,-72.4627742,3a,59.7y,150.62h,89.24t/data=!3m6!1e1!3m4!1sS-koGQlLNbaaNeE6UaTQug!2e0!7i13312!8i6656

[roadman65]

The Bunker Road Tunnel in Marin Headlands, CA. It has a five minute signal at both ends.

Horseshoe Curve in PA has a one lane underpass beneath the rail grade.

[Dirt Roads]

This keystone tunnel runs underneath what used to be a branch of the NYNHH railroad. It's at lease 150 years old and obviously predates the automobile given how narrow it is.
https://www.google.com/maps/@41.8245566,-72.4627742,3a,59.7y,150.62h,89.24t/data=!3m6!1e1!3m4!1sS-koGQlLNbaaNeE6UaTQug!2e0!7i13312!8i6656

Back in the early 1900s, West Virginia was famous for low water roadways where small creeks ran through these "stone culverts" underneath the railroads.  Unfortunately, heavy flooding would build up debris along the walls and when the debris would break loose, the roadbed would completely wash away.  There's one in Braxton County that developed a 30-foot deep pit after the Great Flood of 1949.  An emergency route had to be constructed up and over the railroad at grade.  The creek was much swifter after then, so the original road was never restored.  There's probably a few of these that remain, but all of the ones I knew of are now closed to traffic.

[roadman65]

One on Marin Headlands, CA.