The accident happened around 7:30 p.m. along southbound I-495 near the split for I-95 southbound.
Police say the driver of a pickup truck lost control, left the roadway and rolled several feet down an embankment.
The male driver was seriously injured.
A female passenger was critically injured.
A Labrador Retriever died at the scene. The dog was just picked up from a vet hospital after having surgery.
Both the man and woman were rushed to Christiana Hospital for treatment.
There is no word on why the man lost control of the pickup.
The crash caused the right lane of southbound I-495 and left lane of I-95 North to shut down.
