The man was walking in Waterside Street in Largs in North Ayrshire, around 11.30am yesterday when a lorry with no driver rolled down the street and struck a parked car.
The car then hit the man, trapping him underneath.
Emergency services were called but he died at the scene.
Sergeant Mark McGowan said: "An unoccupied HGV rolled down Waterside Street, Largs and struck a Peugeot 205 which was parked nearby. This resulted in the Peugeot striking the 86-year-old man."