Police are attempting to identity a cyclist who died in a crash on the A61 Dronfield bypass.
The incident happened on the southbound carriageway of the A61 at about 3.20pm on Thursday.
It involved a Citroen C3 and a cyclist who was riding a black and yellow Carrera TDF bicycle.
The cyclist suffered serious head injuries and was taken by air ambulance to Northern General Hospital, in Sheffield, where he later died.
The rider did not have any identification on him and police are appealing to anyone who may be unsure of the whereabouts of a friend or family member who went out for a bike ride and has not returned as expected.
The man was white, aged about 55, 5ft 6ins to 5ft 8ins in height, and with short, grey hair. He had no tattoos but had a small scar to his abdomen. He was wearing black lycra shorts and red cycling shoes.
Anyone with information on his identity should call Derbyshire police on 101.