Home > Multiplexes > Pennsylvania > I-78/PA 309
I-78 and PA 309 join for 7 miles on the southwest side of Allentown in Lehigh County.
The western beginning of the I-78/PA 309 duplex heading east and south. PA 309 enters on the right two lanes, while I-78 is the mainline and left two lanes. The first exit is for US 222 south and PA 222 north and marks the transition between US and PA designations for Route 222.
US 222's exit is the first exit after the merger of I-78 and PA 309.
The following exit accesses the beginning of the southern segment of PA 29. Cedar Crest Boulevard serves the town of Emmaus.
Reassurance shields eastbound, including the old-style state-name interstate marker.
Lehigh Street connects Emmaus to the south with Allentown to the north.
The next exit along the duplex leads to the village of Summit Lawn and to PA 145, which serves Allentown's downtown.
At the following exit, six miles from the beginning of the duplex, PA 309 exits toward Philadelphia while I-78 continues forward to recombine with US 22 in New Jersey.
The eastern split.
A wider, snowier iew of the eastern split. I-78 curves to the left over PA 309
Now in the opposite direction at the opposite split. I-78/PA 309 splits here at the western split. Originally, there was only the PA 309 freeway. I-78 was later built, and this interchange was reconfigured to make I-78 the mainline, with PA 309 entering/exiting on ramps to its freeway.
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