It's about a man (I think) who is maybe hypnotised or in therapy possibly after a car crash and he hears/sees all these things like a car horn, a man's trouser leg pulled up, a necklace(?).
He's on some kind of crusade to discover what happened to his wife/who killed her (?).
SPOILER ALERT At the end of the film we realise he and his wife were in a car accident on a bridge and all those things he saw/heard were from the final moments when the police/ambulance arrived. So he realises he was actually dead or in a coma all along.
Does anyone remember the name of the film from the very sketchy details I can remember?