Matthew Daley had "psychiatric and mental health issues" at the time he is accused of launching into a furious knife attack that killed great-grandfather Don Lock in a suspected road rage attack on the A24.
Daley, 34, of St Elmo Road, Worthing, was arrested at a golf club on 17 July on suspicion of murdering Lock in a violent rage after their cars apparently collided on the West Sussex road the previous night.
On 21 July Daley appeared via video link from Lewes Prison to confirm his name at a hearing at Lewes Crown Court. He was remanded ahead of a plea hearing on 25 September.
Sussex Police launched a murder inquiry after Lock was stabbed a dozen times in his head, neck and back in what was described as a frenzied attack.
Cycling enthusiast Lock was returning home from a social event organised by Worthing Excelsior Cycling Club.
Son Andrew paid tribute to his father, describing him as "full of wisdom, full of wit, always calm".