The crash happened on I-91 in Middlesex County at about 1 p.m. on Tuesday, June 7, according to Connecticut State Police.
A 2007 Toyota Camry was traveling on I-91 southbound near Exit 22S in Cromwell when, for an unknown reason, the car veered into the right shoulder, struck a metal beam guardrail, and rolled over, police said.
The Toyota rolled down an embankment before it came to an uncontrolled rest on its roof, police said.
Authorities said the driver, an 80-year-old man from the Tolland County town of Ellington, was hospitalized for treatment of serious injuries.
The Toyota sustained disabling damage and was towed from the scene, police said.
The crash is under investigation.
Police asked anyone who witnessed or has information about the crash to call Trooper Abotsi at 860-534-1000.
Click here to follow Daily Voice Middletown and receive free news updates.