Pennsylvania Roads - I-78/US 22/PA 309 EB/SB

I-78 EB (US 22 EB, PA 309 SB)


Courtesy Lou Corsaro.


Eastbound up to the US 22/I-78 split west of Allentown, with a cool diagrammatic sign. From I-81 to here, I-78 runs along the old four-lane freeway that once was just US 22 - the original 22 runs nearby as a two-lane road. Due to its age, some clearances are a little low and the design is highly substandard. I-78 was originally supposed to follow what is now US 22 up around Allentown/Bethlehem, across to Phillipsburg, NJ, and back into the current alignment at Exit 3, meaning US 22 would be held captive until past Clinton. However, NJ was not able to upgrade US 22 to a freeway for those few miles, and PA's freeway isn't Interstate-quality near the NJ border anyway, so the next proposal was to break off of the US 22 corridor at West Easton, cross south of Easton and north of Alpha, NJ, and back into the current alignment at Exit 3. I guess West Easton threw a fit over that, so a whole new southerly alignment was built through PA instead. (Alpha later threw a fit and insisted I-78 loop to the south instead of slicing neatly across the north.) I-78's Bethlehem child, I-378 (a babe born in Bethlehem...), became PA 378, albeit a little belatedly. Maps showed I-78 along US 22 for quite awhile, though, and it was signed there despite the non-freeway discontinuity. See the US 22 page for more.


Not sure between which exits the last sign is, but Quakertown is on PA 309 and Bethlehem is Exit 67, so this is about right. The Exit 57 1-mile advance is courtesy Mike Byrnes.


Between the last run of photos and these, I have the same complaint as on the westbound page - all these Allentown exits would be better served by an "Allentown - Next N Exits," versus the piecemeal way that leaves you guessing exactly when you've actually passed the city. Also, between the gore and the exit ramp sign for Exit 57 (the last two signs respectively), it appears that once this was an A-B exit, but configuration probably hasn't changed since this became I-78. Back when it was PA 309, the exit ramp was a lot tighter here, and the now WB-only Exit 58 immediately to the east was a full exit.


The last one is on the exit ramp, and is button copy. PA 145 becomes PA 309 at Exit 60, but since I-78 is currently multiplexed with PA 309 along 309's original path, it's a pretty tight diagonal corner, which is why the EB-NB and SB-WB movements happen to the west.


West Rock Rd. NB, turning left from the previous exit ramp photo and approaching PA 145.


Only the left "LAST EXIT" sign is button copy, and to prove it, click on that last photo. Not sure how that came about, unless it's due to a hapless trucker.


Running up the last exit ramp in Pennsylvania, but wait, there's more!


Phillipsburg is much closer than 5 miles from that sign, but a long loop around the south of Alpha means drivers have to go all the way to Exit 3 in Alpha, NJ, and then head back northwest. US 22, of course, runs right through it, and Phillipsburg is what prevented 22 from becoming I-78's through route.

Switch to the WB side
Roads intersecting I-78
Exit 51 to US 22 alone
Exit 51 or 60 to PA 309 alone
Back to I-78 main page


Follow I-78 into NJ
Exit 35 to PA 143
Exit 51 to I-476
Exit 54 to US 222
Exit 55 to PA 29
Exit 55 to Cedar Crest Blvd.
Exit 67 to PA 412
Exit 75 to PA 611
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