The 31-year-old driver, who remained anonymous throughout the trial, was liable to one to two years in prison after being found guilty of road homicide.
Judge Vinicio Canatarini reduced the sentence to one year, the reasons for which he will reportedly reveal in 90 days’ time.
The accused has had his driving licence revoked and will pay all court costs.
The court heard that Hayden was travelling on a bicycle as part of training when he was hit by a Peugeot at 70 km/h on a road in Rimini with a 50 km/h speed limit on May 17, 2017.
The 35-year-old Kentucky native suffered severe brain damage and abdominal injuries.
He died five days later in hospital.
An expert witness for the prosecution alleged the driver could have “entirely avoided the accident” if he was travelling at the legal speed limit.
Defence lawyers argued that Hayden had failed to observe a stop sign, and was listening to music while cycling.
An official accident report attributed 30 per cent of blame to the driver.