It was around 3:10 p.m. when the Plymouth Breeze the teens were in was headed eastbound on Hyett's Corner Road, and stopped at the stop sign at the intersection with Dupont Parkway.
While attempting to make a left turn onto northbound Dupont Parkway, a southbound tractor-trailer collided with the driver's side of the Plymouth.
The driver of the Plymouth, identified as 17-year-old Kevin Langan of Newark, was transported to Christiana Hospital and admitted in critical condition.
Two passengers in the car, 17-year-old Danielle Slaughter of Bear and 16-year-old David Dudley of Newark, were transported to Christiana Hospital with non life-threatening injuries.
The driver of the tractor-trailer was not injured.
All three teens injured in the accident are in the 11th grade at St. Georges Technical High School in Middletown and had just left the school at the end of the day when the accident occurred.
Police are continuing their investigation and no charges have been filed.