The 35-year-old, who switched to the World Superbike Championship in 2015 but made two final MotoGP appearances last season, was hit by a car while training on his bicycle at around 2pm near the Misano circuit in Rimini, Italy.
Hayden was transported to a local hospital with ‘extremely critical’ head, chest and pelvic injuries, then on to the intensive care unit of Maurizio Bufalini Hospital in Cesena.
A hospital statement issued on Thursday said Hayden had suffered “a serious polytrauma”, which is a medical term to describe the condition of a person who has multiple traumatic injuries.
Although Hayden only won three MotoGP races, he was every inch a champion, both on and off the track.
Known as the “Kentucky Kid”, Nicky Hayden arrived in 2003 in MotoGP with his number 69 in the race, the same as his father, and won his only world title three years later on the handlebars of a Honda HRC. With five small points ahead of the outgoing champion, he was the first to advance to the championship the Italian Valentino Rossi (Yamaha) in the category queen.
He had hidden a wound following an accident during the penultimate race in Portugal and clenched his teeth to compete in the Valencia GP, the final event of the season, where he was crowned by finishing third while his rival Finished 13th after falling. He retired in the following seasons and remained at the helm of a MotoGP until 2015, then punctually for two replacements in 2016. In Superbike, he finished 5th in the championship last season but was only in 13th place this year .