Around 1:30 Tuesday, two cars collided on US-25 near the Berea Bypass.
According to police the driver of a compact SUV crossed over the yellow line and collided with a pickup.
There were two people in each vehicle. They were all transported to area hospitals with what is believed to be life-threatening injuries.
Reconstruction responded to the scene. A dog was killed in the crash. He was riding in the pickup when the load in the bed crashed through the back window.
Berea Police is being assisted by Kentucky State Police, Madison County EMS and the Berea Fire Department.
Police said that they have had accidents here in the past.
Authorities said the cause of the accident may have been distracted driving.