Donald Bennett was struck by the unattended vehicle after a police officer responded to a disturbance in Pudsey Park in June 2013.
The van is believed to have rolled forwards and collided with the 83-year-old former joiner as he reportedly sat on a wall eating an ice cream after a visit to the park with his son.
An inquest into his death starts at 10am today (Sept 22) at Wakefield Coroner’s Court and is expected to conclude by Friday.
West Yorkshire Police referred the incident, which happened at around 2.15pm on a Saturday, to the Independent Police Complaints Commission and they launched an inquiry.
An investigator from the IPCC was sent to the scene and met with members of Mr Bennett’s family at his home in Pudsey.
Cindy Butts, then IPCC commissioner for West Yorkshire, said at the time: “I will ensure our investigation is robust and that it provides the answers Mr Bennett’s family and friends will understandably want.”
A police officer involved in the incident was not suspended from duty but was suspended from driving duties pending the outcome of the IPCC’s inquiry into the tragedy.