Witness Amanda Dittig recorded the collision as it happened around 10:15 a.m. Tuesday on I-78 West in Lower Saucon Township, Pa.
Police say all three vehicles, the school bus, a Fed-Ex tractor trailer, and a tanker trailer, were all traveling westbound on 78 in the center lanes.
While heading up a hill, the bus started to have engine problems causing the driver to slow down.
Police say as the school bus was decelerating, the Fed-Ex tractor trailer driver attempted to go around it.
The bus driver, police say, then attempted to drive into the right shoulder and was sideswiped by the Fed-Ex truck.
After striking the bus, police say the driver of the Fed-Ex truck lost control, traveled across both the center lane and left lane, and struck a tanker trailer.
The bus, contracted by the Wayne Board of Education, was transporting seniors from Wayne Valley High School to an end of the year class trip at Dorney Park in Allentown.
37 students were on the bus along with a teacher and guidance counselor. Five students along with one of the school employees and the bus driver were taken to Saint Luke's Hospital - Anderson Campus in Easton.
School officials say the remaining students, who were not injured, were then transported to Dorney Park where they were evaluated by a Wayne Valley High School nurse.
"Additional counseling support for our students will be offered by the school district as needed," a statement from the school read.
The drivers of the Fed-Ex truck and the tanker trailer were taken to St. Luke's University Hospital - Bethlehem Campus.
I-78 westbound was closed for approximately two hours.
Pennsylvania State Police is continuing to investigate.