The crash occurred around 1:15 p.m. in the southbound lanes near the Pennsylvania Avenue interchange.
Investigators say the woman was driving northbound in the southbound lanes when her vehicle collided with the tractor-trailer.
Chopper 6 was over the scene where a car was wedged between the semi and a cement median.
The woman was transported to a nearby hospital, where she was pronounced dead. She has been identified as Vivian Angela Perri, according to police.
The driver of the tractor-trailer was taken to Jefferson Bucks Hospital with unknown injuries.
Route 1 was closed in both directions for several hours as police investigated the crash.
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