Underlying heart problems may have caused an experienced cyclist to make a fatal swerve on the Dronfield bypass.
Retired teacher Malcolm Cottam, 67, died of “catastrophic” injuries after a horror smash on the A61 between Sheffield and Chesterfield last summer.
Mr Cottam – who was riding his pedal bike alongside the slow lane of the southbound carriageway – drifted into the road and collided with a car.
The tragedy may have occurred because Mr Cottam – who was described by his family as a “very fit person” – suffered a lapse in concentration caused by heart disease.
Chesterfield coroners’ court heard on Tuesday how Laura Colland was driving her Citreon C3 down the bypass at about 3.20pm on July 31 when she saw Mr Cottam.
She attempted to move into the fast lane but was unable to make the manoeuvre because of another vehicle.
As she moved back to her position in the slow lane, Mr Cottam swerved into the carriageway.
Coroner James Newman said: “As a result of these two movements – him moving out, her moving back in – there was a meeting and he suffered catastrophic, multiple injuries.”
Pathologist Dr Andrew Hitchcock said tests revealed Mr Cottam had ischemic heart disease.
He added: “Given the pressure his heart was under at the time, it’s possible he suffered from an acute cardiac event.”
Police investigations revealed there were no mechanical problems with either Ms Colland’s car or Mr Cottam’s bike.
There were no defects on the road and there was no wind which may have caused Mr Cottam to drift into the carriageway, police said.
Recording a conclusion of accidental death, Mr Newman said: “Why did he move out?
“The most likely reason was a loss of concentration due to some medical event.
“He may not have shown any symptoms of heart problems but he did have significant heart disease.
“That’s the most likely reason but it’s not proven.”
Speaking during the inquest, Mr Cottam’s family paid tribute to him.
They said: “Malcolm was a very fit person who had ridden on the Dronfield bypass for about 20 years.
“He was an experienced cyclist and loved getting out and about on his bike.
“He was a very active man and always loved to be among people – he was always doing something.
“We loved him – he was great.
“He’s missed by all his family and friends and indeed the community.”
Mr Cottam, of Norton Park Crescent, Norton, had a number of interests including archery, art and baking.
After his death, Mr Cottam’s body lay unidentified in a mortuary for a week.
The retired Outwood Academy City teacher lived alone and had not been reported missing.
• For more information about heart disease, visit www.nhs.uk