Christopher Colegate, 69, was found in the road at the junction of Heath Avenue and Darby's Lane in Poole, at about 19:30 GMT on Friday 13 December.
He suffered significant injuries and later died at Poole Hospital.
Despite numerous appeals and rewards of £11,000 being offered, the driver of the car has never been found.
Dorset Police have renewed their appeal for witnesses.
Officers believe a light-coloured VW Golf Mark 4, made between 1998 and 2005, was involved in the collision.
Mr Colegate, from Poole, walked with a "distinctive stoop" and used two walking sticks.
Inspector Matt Butler, of the Dorset Police traffic unit, said: "We still do not know exactly what happened to Mr Colegate.
"We know that a number of cars were in the area at the time of the collision.
"Some we have traced but we have not been able to identify a Golf driver that travelled along Heath Avenue toward Wimborne Road at around the time of the incident."
Dorset Police and Crimestoppers are still offering a £10,000 reward, while Oakdale Conservative Club, which Mr Colegate regularly attended, has offered an extra £1,000.
A hit-and-run driver who fled a collision in which a man was killed in Dorset is still being hunted a year on.