An NHS trust could have prevented the killing of a man who was stabbed to death by a mental health patient, a report has found.
Matthew Daley, 35, killed Donald Lock on the A24 in Findon, near Worthing, in 2015 after the 79-year-old ran into the back of Daley's vehicle.
In the report, NHS England said Daley did not receive proper treatment for his psychotic behaviour.
Sussex Partnership NHS Trust apologised and admitted it "got things wrong".
Daley was convicted of manslaughter in 2016. He admitted killing Mr Lock, who was stabbed 39 times, but claimed diminished responsibility.
He was sentenced to life and will serve at least 10 years.
The Sussex Partnership NHS Trust did not "make robust assessments in relation to psychosis and autism" and this led to a "flawed set of assumptions" about how to manage Daley, the report said.
It concluded this position had denied Daley the opportunity to receive appropriate treatment.
Inspectors went on to write that in their view Daley's levels of violence had increased "such that serious harm to others was increasingly likely".
They acknowledged staff "could not have predicted" Daley would kill, but said "the tragic death of Mr Lock may have been avoided" had he received effective therapy.
The report made 21 recommendations for the trust to address.
In a statement the trust's chief executive, Sam Allen, accepted the report's findings.
She said: "We should have acted differently in relation to the care and treatment we provided to Matthew Daley and I apologise unreservedly for this."
"We didn't attach sufficient weight to his psychotic symptoms or his non-compliance with medication. We then failed to listen to the concerns of Matthew's family and to undertake a clinical review of his care.
"As a consequence, we missed the opportunity to explore other treatment options such as therapy or hospital admission."