The collision involved a bus and a motorcycle
A 20-year-old man died when his motorbike collided with a moving bus in Brighton.
The man, from Seaford, was pronounced dead at the scene of the accident, in Ditchling Road, at 15:55 GMT.
Police said his Kawasaki motorbike collided with the bus and crashed into a lamppost.
His pillion passenger, a 20-year-old woman from Newhaven, was taken to hospital with serious injuries. She remains in a critical condition.
Sgt Clare Kenward, from Sussex Police, urged any witnesses to the collision to contact officers.
She said: "Our thoughts are with the family of the young man who has sadly died and with the injured woman, who remains in a very serious condition in hospital."
Police closed Ditchling Road causing severe tailbacks during the rush hour.
