Police are appealing for information from drivers in St Albans after a motorcyclist died on the A1.
Shortly before 7pm on Friday, February 7 a red Honda motorbike was on the northbound carriageway, when the rider lost control before the Hatfield tunnel.
The reason for the loss of control is not yet known, but it is thought the motorbike made no contact with any other cars on the road.
The man, in his 20s, suffered serious injuries and was rushed to Lister Hospital in Stevenage, where he was pronounced dead.
It is believed a number of other vehicles were involved in a separate crash, because drivers took action to avoid a crash with the motorbike. No one else was hurt.
Road policing Sergeant, Peter Scholes said: "I am keen to trace the driver of a dark coloured vehicle that was traveling a short distance from the motorbike when the incident occurred.
"I'd also like to speak to anyone else who saw the motorbike before the collision when it was travelling either on the A1(M) or the A414 from St Albans. These people might have information that is vital to establishing what happened in the moments leading up to the collision."
Anyone with information can contact PC Scholes via the police non- emergency number 101.