Divided highways with weird off grade intersections.

[MCRoads]

This is a thread about divided highways going over and under an obsticle. Here is an interesting oddity north of Amarillo:

https://goo.gl/maps/1KNRxYYN8vN2

I think the highway had one carriageway, and went under the tracks, but when the road was widens, the underpass couldn't be widened, so they built a bridge over the tracks to save money. Any more of these? Is my theory right?

[GaryV]

There's a configuration like that west of Chelsea, MI on I-94:  https://www.google.com/maps/@42.2946212,-84.0859395,1295m/data=!3m1!1e3?hl=en

As far as I know, this highway was devised in that manner; both sides were built at the same time.  Old US-12, that the freeway replaced, is about 1/2 mile east of the railroad.

[vdeane]

The New Jersey Turnpike does this at exit 7; normally, ramps from the car lanes go over the truck lanes, but here the reverse happens, since the truck lanes were added later and exit 7 wasn't rebuilt as part of the project.
https://goo.gl/maps/RdCEguCyfJx

[Tom958]

Here's one I thought was cool-looking enough to photograph. This is GA 72 westbound west of Elberton. The lower roadway was built to its current state in the mid '60's, and the higher roadway was added in 1999, IIRC. The new bridge is pretty long as well as high and has T-shaped piers, which looked really cool when it was first built, but the trees in the median are so tall and dense now that you can barely even see the bridge.

[TheHighwayMan3561]

There's a configuration like that west of Chelsea, MI on I-94:  https://www.google.com/maps/@42.2946212,-84.0859395,1295m/data=!3m1!1e3?hl=en

As far as I know, this highway was devised in that manner; both sides were built at the same time.  Old US-12, that the freeway replaced, is about 1/2 mile east of the railroad.

There's another one on I-94 (and 90/39) southeast of Portage, WI. I'm not sure what road is being "  undoverpassed there.

[Brian556]

I-35 at Cesar Chavez St in Austin Tx:
https://www.google.com/maps/@30.2616588,-97.7363717,3a,75y,173.73h,81.95t/data=!3m7!1e1!3m5!1sy6PJ-E0XPuDDwboB8TftoQ!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3Dy6PJ-E0XPuDDwboB8TftoQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D15.871571%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656?hl=en-US

[wanderer2575]

The Lodge Freeway at the Davison Freeway in Detroit, MI.

The Lodge Freeway at Telegraph Road in Southfield, MI, with I-696 between the Lodge carriageways.

[NE2]

There's a configuration like that west of Chelsea, MI on I-94:  https://www.google.com/maps/@42.2946212,-84.0859395,1295m/data=!3m1!1e3?hl=en

As far as I know, this highway was devised in that manner; both sides were built at the same time.  Old US-12, that the freeway replaced, is about 1/2 mile east of the railroad.

A 1955 aerial shows only the westbound side existing (as an undivided surface road).

[jakeroot]

The 405 south of Bellevue, Washington formerly had a grade situation like in the OP. Northbound 405 went over the railway, but southbound 405 went through a tunnel below the railway: https://goo.gl/PwBHLs

The tunnel was built in the 70s, replacing what was originally an underpass beneath the railway. The southbound carriageway was built before the northbound carriageway (in the 40s, as Secondary State Highway 2A). The terrain is quite hilly through there, so when the 405 was built, it must have been decided that a bridge over the railway for the NB carriageway was easier than twinning the original road. The tunnel, and the railway that travelled above it, were eliminated in 2008.

[GaryV]

There's a configuration like that west of Chelsea, MI on I-94:  https://www.google.com/maps/@42.2946212,-84.0859395,1295m/data=!3m1!1e3?hl=en

As far as I know, this highway was devised in that manner; both sides were built at the same time.  Old US-12, that the freeway replaced, is about 1/2 mile east of the railroad.

A 1955 aerial shows only the westbound side existing (as an undivided surface road).

You are correct.  I didn't realize that the road now known as "Old US Hwy 12" which goes through Chelsea is really the "old-old" route.  Chelsea was bypassed in 1940 with a two-lane routing of US-12, and that roadway was twinned to make I-94.

[MCRoads]

What about:

https://goo.gl/maps/qmZrUSJuqsx

Which one was built first? I think the bridge was built first, then the tunnel expanded the road to 4 lanes.

[sparker]

There were several of these along CA (former US) 99 in the San Joaquin Valley:  one just south of Famoso (the CA 46 junction), one at CA 198 (the original interchange was built around this split-level separation), one at Chowchilla just north of the CA 152 interchange, and the final example south of Elk Grove just south of the Grant Line Road interchange.  The latter two remain in their original "over/under" format; the other two were replaced by simple twin overpasses on CA 99.  Curiously, the "under" segment at the 99/198 interchange is still in use, functioning as the carriageway for eastbound CA 198. 

[NE2]

What about:

https://goo.gl/maps/qmZrUSJuqsx

Which one was built first? I think the bridge was built first, then the tunnel expanded the road to 4 lanes.

http://www.google.com/search?q=belle+chasse+bridge

[Michael]

Ever since I first saw the over/under bridges of I-81 and PA 307 in 2002 or so, I thought it was weird.  I'm guessing it was built that way due to the terrain.  I can't think of any other over/under bridges I've seen off the top of my head.

[cl94]

I can think of a couple off the top of my head...

- Taconic State Parkway over NY 129. Parkway here was originally 4 lanes undivided on the right, new alignment built on the left in the late 60s-early 70s when the Taconic was widened to 6 lanes. There are two more in this area, one being at the next interchange north, another south of the reservoir. Both were constructed as such because of the realignment.
- I-80 and I-271 south of Cleveland. This is due to terrain.

[JKRhodes]

The Grand Avenue railroad bridges in greater Phoenix have an over/under configuration similar to the OP:

https://goo.gl/maps/y2KLpUByxix

In fact, the entire Grand Ave corridor from I-17 to Surprise has a bevy of unique bridge configurations and partial interchanges, due to an effort undertaken in the early 2000's by ADOT to eliminate busy 6-leg intersections, railroad crossings, and improve overall throughput along the route. In some cases, Grand Ave got the bridge. In others, the major arterial route it crossed got preference depending on need.

The most recent upgrade, which isn't visible on google maps as of right now, is at Bell Road where a new bridge carries Bell over the railroad and Grand Ave. Access between the two roads is via ramps in the median of Grand Ave:
https://www.surpriseaz.gov/3181/Bell-Grand-Interchange-Improvements

[BrianP]

This is a thread about divided highways going over and under an obsticle. Here is an interesting oddity north of Amarillo:

https://goo.gl/maps/1KNRxYYN8vN2

I think the highway had one carriageway, and went under the tracks, but when the road was widens, the underpass couldn't be widened, so they built a bridge over the tracks to save money. Any more of these? Is my theory right?

I'm not sure that money would be the #1 motivator.  I would guess that the #1 motivator is to not disrupt the railway line.  You can do that easier by building a bridge over the railway line than adding a bridge for the railway line to cross. You can certainly do the latter by building a temporary track around where the bridge is built.  But the former sounds cheaper since even a temporary track needs to be able to support the weight of a train. So money would be the #2 motivator IMO. 

If you could disrupt the railway line then avoiding a temporary track and just building a new bridge for the railway line to cross sounds like the cheapest option.  But then again I'm not a rail geek. 

[Revive 755]

Not related to interchanges

* Two on US 36 in Missouri:  One near Callao, and another near Bucklin

* One in Tennessee between I-40 and TN 299/Airport Road

* One on the West Virginia Turnpike

Related to interchanges
* I-55 has two in East St. Louis, Illinois:  One at the interchange with the MLK Bridge, and another a short distance east at the interchange with I-64 and I-70,.  At both of these the top level of ramps were not part of the original interchanges.

* I-44 at I-55 and Gravois south of Downtown St. Louis

* IIRC, I-40 used to have one east of I-275 in Knoxville, Tennessee

Other
*There's always the western double deck section of US 40 in St. Louis

[JREwing78]

There's a configuration like that west of Chelsea, MI on I-94:  https://www.google.com/maps/@42.2946212,-84.0859395,1295m/data=!3m1!1e3?hl=en

As far as I know, this highway was devised in that manner; both sides were built at the same time.  Old US-12, that the freeway replaced, is about 1/2 mile east of the railroad.

That's OLD-old US-12. Half of the current I-94 (WBD, I believe) between Chelsea and exit 147 near Jackson was an improved 2-lane US-12 originally, then the other carriageway was added later. The WBD side was constructed in the mid-1930's, opening to traffic in 1937. The EBD side was likely constructed in the early 1950's, prior to the 1959 designation of I-94. More: http://www.michiganhighways.org/listings/US-012.html

For the most part, it's invisible, but you'll notice just east of exit 147 the WBD lanes follow the terrain more closely while the EBD lanes are very level. The over-under railroad crossing just west of Chelsea is the other dead giveaway - the WBD underpass (particularly with the steep climb immediately following) is evidence of the route's pre-Interstate heritage. EBD has it's own quirkiness - that sharp right curve immediately east of Kalmbach Rd to obtain sufficient clearance away from the WBD underpass, then a sharp left to come back to the original alignment.

If MDOT was to rebuild this stretch today, it would route all 6 lanes (because traffic definitely warrants it) directly between the existing EBD and WBD lanes as an overpass, with a more gentle curve.

[CNGL-Leudimin]

The ultimate example of this is A282 East of London, UK .

[US 81]

I-35 at Cesar Chavez St in Austin Tx:
https://www.google.com/maps/@30.2616588,-97.7363717,3a,75y,173.73h,81.95t/data=!3m7!1e1!3m5!1sy6PJ-E0XPuDDwboB8TftoQ!2e0!6s%2F%2Fgeo3.ggpht.com%2Fcbk%3Fpanoid%3Dy6PJ-E0XPuDDwboB8TftoQ%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D15.871571%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656?hl=en-US

I came here to cite this one. The architecture looks (to my amateur eyes) to date from the 1950's and the original construction of I-35. Were the southbound lanes the original path of US 81 and/or East Ave, does anyone know?

[signalman]

I-287 at I-80 in Parsippany, NJ does this.

https://www.google.com/maps/@40.8637455,-74.4178581,875m/data=!3m1!1e3

[Ian]

The I-65 and I-20/59 junction in Birmingham, AL has a case similar to the OP. The north/eastbound lanes of I-20/59 go over I-65, while the opposite direction goes under it.

I-376/US 22/US 30 passing the 10th Street Bridge in Pittsburgh, PA is another example. Eastbound traffic passes under the bridge, while westbound passes over.

[jakeroot]

I wasn't going to post this, but it's in the same vein as many others above me. The 405/518 interchange with the 5 in Tukwila, Washington has a westbound carriageway that goes over the 5, whereas the eastbound carriageway passes beneath the 5. This is simply due to the design of the interchange, with the left-side ramps for various movements, requiring some higher bridges.

See here on Google Maps: https://goo.gl/fSZaRw -- and here on Historic Aerials, back in 1968, around when the junction was built: https://goo.gl/Dq7e5k

[GaryV]

^ That reminds me of another one.  I-196 goes above (wb) and below (eb) US-131 in Grand Rapids.  At the same location US-131 switches left/right, to create a kind of diverging diamond interchange.