ST. JOHNS COUNTY, Fla. -- Traffic is once again running smoothly on Interstate 95 southbound in St. Johns County.

Two horrible crashes shut down a portion of the interstate Thursday morning and caused major delays.

The first crash happened near International Golf Parkway, according to Florida Highway Patrol Sgt. Dylan Bryan. A Honda Accord driven by 23-year-old Jennifer Edwards rear-ended an 18-wheeler driven by 60-year-old Roy Schultz.

Edwards was hit by by another Honda Accord driven by 48-year-old Shelley Prendes after it side swiped Edwards' vehicle. Edwards was taken to Orange Park Medical Center by air ambulance in life-threatening condition, Bryan said.

A semi driven by 37-year-old Juan Sariento then hit that same Honda while trying to avoid the crash. Charges are pending further investigation in this crash, according to an FHP report.

A second accident happened about four miles north of the first accident.

A Ford Explorer driven by 38-year-old James Harris did not realize the cars ahead were stopped, tried to swerve and lost control.

The Explorer hit a tractor trailer driven by 39-year-old Ronald Lynn Gardner and another vehicle driven by 32-year-old Jolie Hoyt before flipping over, then hitting another vehicle driven by 47-year-old Damon Deas.

Harris was taken to Baptist Medical Center with serious injuries. Hoyt was taken to Orange Park Medical Center with life-threatening injuries.