The man who died in a crash in Ripponden on Tuesday morning has been named.
Russell Arden, 54, from Berry Brow, was killed in the crash at the junction of Baitings Road and Rochdale Road.
He was driving a Saab which hit two horses which were loose on the carriageway.
Both horses also died in the accident.
Police believe the Saab was also in collision with a Corsa and a Ford Fiesta, which hit with one of the dead animals.
The driver of the Fiesta was taken to hospital with minor injuries.
Detectives have appealed for witnesses and have asked horse owners in the area to check their fences.
Detective Sergeant Carole Clayton of the major collision and inquiry team, said: “At this stage we are unable to rule out that the horses have been let out of their enclosure.
“We would ask that all horse owners in and around this area check their fences and enclosures and if there have been any attempts made to remove their horses to contact the Major Collision and Enquiry Team on 101.”
Rochdale Road was shut between Ripponden crossroads and Turvin Road for over six hours and buses were forced to divert through Sowerby Bridge while the road was shut.