A man died and a woman is in critical condition following a road collision on the A57 at Aston in the early hours of this morning.
The incident happened at around 1am on Aston Way, near to the M1 junction 31 roundabout and the fire station, on the carriageway going towards Sheffield.
A moped was involved in the crash, though it is currently unclear who the rider was.
The road is closed while police carry out enquiries at the scene, and is likely to remain closed for several hours.
Police believe the collision may have involved a second vehicle, which would probably have frontal damage.
They are appealing for the driver to come forward, or anyone who may have seen a damaged vehicle that could have been involved in a collision.
Witnesses, or anyone with information, should contact South Yorkshire Police on 101. Alternatively call Crimestoppers anonymously on 0800 555 111.