I-80 has no tunnels in Pennsylvania.
The PA Turnpike has three between Philly and Pittsburgh, as I recall.
OK, that's probably what it was. We were on our way to Pittsburgh from MA when our #2 son was at Carnegie Mellon. We only went that way once. The next time we went on I-84, then cut through the Poconos by Tobyhanna State Park, caught 380S, and got on I-80W, South of Wilkes Barre/Scranton. It wasn't a bad ride.