During weekly training covering ladder operations, the company was sent to I81 NB MM50 for an accident. Engine, Squad, Traffic, and Chief 133 responded. Crews arrived to find a vehicle had crossed from SB to NB and hit a tractor trailer and assisted with EMS and checking for hazards. Chief 7 held the response to 33, 41, Traffic 3, and EMS. Traffic 33 remained until released by PSP.