A cyclist was killed when she was struck by a container that toppled off a trailer on the A63 in Hull.
Fifty-four-year-old Susan Russell, from Hull, died at the scene of the crash earlier.
It happened at the roundabout with Victoria Dock at about 0730 BST. The road was shut until about 1450 BST.
The 46-year-old tractor driver was arrested in connection with the incident and remains in police custody, Humberside Police said.
Officers said a white tractor unit and trailer, carrying a container, were on the roundabout when the container came off and hit the cyclist.
Police want to speak to anyone who saw the tractor unit and trailer before the accident.
They would particularly like to speak to the driver of a silver vehicle, believed to be a Ford C Max, who initially stopped at the scene.
Humberside Police shut the road in both directions for several hours, causing major traffic disruption