A lifelong Norwich City fan who was driving home from a match drowned in a river after a road closure sign leading to a ford was left face down by the roadside, a coroners' court heard.
Barry Howard, 75, died when his car was swept 30m (100ft) down the River Tas near Newton Flotman on 13 December.
At his inquest, Norfolk County Council said it did not know how the sign at Shotesham Ford ended up on the verge of Mill Lane and that it was working on a permanent safety solution.
Area coroner Samantha Goward said she was concerned by the council's response to the "tragedy", and that it should take action to prevent future deaths.