Police drove past the crashed vehicle, which was obscured by a passing truck, but returned to the scene some time later.
Hooper said the man got out of his car and, before police reached the scene, a camera operator saw the man climb over the motorway barrier, where he fell.
“Police patrols were immediately deployed to the commercial area below the Newmarket flyover and provided first aid,” he said.
The man died at the scene.
“This is a tragic event for all those attending staff and welfare has been put in place for our people.”
Hooper said police were in contact with the dead man’s family and have notified the Independent Police Conduct Authority of the incident.
“The Serious Crash Unit attended the scene on the Newmarket flyover and carried out an examination.
“A critical incident investigation has been established to fully understand what occurred this morning.”
As part of that investigation, a post-mortem examination will be carried out, with formal identification procedures to be completed.
Sign up to The Daily H, a free newsletter curated by our editors and delivered straight to your inbox every weekday.