 Upon completion of the freeway in 1968, the new highway was designated I-378, a spur off of I-78.However, in 1970, as I-78 was realigned to a new bypass to the south of Bethlehem, I-378 was decommissioned and replaced with the alignment of PA 378 the following year.Since completion, PA 378 has undergone little major change, but the highway has undergone several rehabilitations.