Ghost ramps? Aborted interchange design? (On I-80 in PA)

[briantroutman]

I have noticed this oddity on several occasions driving I-80 between DuBois and Brookville. At the PA 830 interchange (Exit 86), where ramps appear to exit to the right, the land also appears to be perfectly graded for ramps exiting leftward through the median and up the the overpass.

This is what you see westbound–note the actual ramp on the right and the grading on the left.


It's also pretty visible from the aerial view.


And here's the location.
http://goo.gl/maps/R2QUk

I don't think it's one of the many dormant crossovers that are commonplace on I-80 in PA because the opposing ramp grades do not form a continuous path from the eastbound lanes to the westbound lanes and vice versa. In addition, there is a crossover just over a mile east of the interchange.

It wouldn't make sense as a construction vehicle or police access road because there is a complete interchange right there.

The oldest map in the USGS archive (http://bit.ly/Vnq8iu) shows the interchange with the present layout as of 1968, so if it had been reconstructed, it must have been a very early revision.

So does anyone know or have a guess as to why this is here? Perhaps a temporary end of I-80 in the '60s? A partially constructed left-exit interchange that was reconsidered and rebuilt?

[PAHighways]

Current Exit 86 was a temporary terminus from 1964 until 1970.

The only thing I could think of is that those were temporary haul roads on the eastern side of the interchange during and temporary on/off ramps on the western side.

[NE2]

Probably graded and used when one direction was closed for repaving.

[briantroutman]

Well...I thought we had the definitive answer. But maybe not.

If it was tied to the initial construction process, it would seem to be an odd setup. I have seen numerous freeways that end at a diamond (with plans for future expansion), and traffic is nearly always funneled up the actual ramp that later becomes a permanent exit once the freeway is extended.

Never thought of the temporary repaving situation. That would make sense, although it would suggest that the grading wasn't there when I-80 was built and maybe added in the late '70s or '80s for a resurfacing project.

[NE2]

the grading wasn't there when I-80 was built

This is true: http://data.cei.psu.edu/pennpilot/era1970/jefferson_1969/jefferson_1969_photos_jpg_800/jefferson_051569_apn_6jj_21.zip

[akotchi]

It is more likely that these were temporary ramps to/from a temporary two-way roadway while the other roadway was closed for reconstruction.  A lot of I-80 across Pennsylvania was rebuilt from the base up using this traffic pattern.  I recall driving through much of this section years ago.

[Duke87]

It is more likely that these were temporary ramps to/from a temporary two-way roadway while the other roadway was closed for reconstruction.  A lot of I-80 across Pennsylvania was rebuilt from the base up using this traffic pattern.

"Was". Does this mean they've finally finished? They've been at it for at least a decade by this point. Guaranteed you will hit traffic somewhere thanks to the single laning.

[akotchi]

Good point . . .

[Alps]

It is more likely that these were temporary ramps to/from a temporary two-way roadway while the other roadway was closed for reconstruction.  A lot of I-80 across Pennsylvania was rebuilt from the base up using this traffic pattern.  I recall driving through much of this section years ago.

I've never seen PennDOT (or any other agency, for that matter) construct temporary ramps in a scenario like this - but then again, usually the carriageways aren't so far apart.

[seicer]

It's evident in both directions, but it doesn't look like the highway was rebuilt: http://goo.gl/maps/xUXr7. Note the asphalt pavement with the joints exposed through the patching - it's most likely the original concrete down below. Even the ramps feature what seem like an original concrete base.

The NBI lists both of those overpasses as 1962.

[vdeane]

That doesn't necessarily mean the original concrete is there.  In the northeast, concrete only lasts 20-30 years, so if it was built in the 60s, it's due for its SECOND replacement now!

[PurdueBill]

The Historic Aerials site has only one aerial (2006) but topos from 1994, 1988, 1973, and 1968 that show I-80 and the current ramps, but no show of the grading for the left ramps.  Could they be more recent than 1994?  Are they just something that didn't get included in the topographical map if they came and went between maps?  One would think that at least the vestigial grading would show up on a topo map somehow.  The 2010 topo does have some different countours right around the left ramps than the older ones, so either stuff caught up several cycles after the ramps/grading came and went, or the ramps/grading are younger than we might think.

[Alps]

That doesn't necessarily mean the original concrete is there.  In the northeast, concrete only lasts 20-30 years, so if it was built in the 60s, it's due for its SECOND replacement now!

Concrete only lasts 20-30 years as a smooth surface, maybe, but there's also cost of replacement and limited budget to factor in. They're just now replacing 40-year old concrete on heavily trafficked I-80 in NJ.

[SteveG1988]

Concrete and lifespan varies on the road, for example I-295 in NJ near me was built mostly in the 70s, as such the concrete in sections is original but not in the best of shape, and several sections were redone in 2003, and are being redone now,