The footage shows a huge dent and a smashed windscreen on the passenger side of a black Peugeot 207CC.
Police then arrive at the scene and are seen taking pictures of the footwell.
Discarded on the side of the road is the bike Hayden was riding when he was knocked off.
Police quickly blocked off the road and are visible directing traffic away from the crash site.
The hazard lights of the vehicle that hit Hayden off, meanwhile, are flashing.
The American collided with a car while cycling on the Rimini coastline.
He was in Italy having raced in the World Superbike Championship last Sunday.
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Nicky Hayden crash video: The dent in the windscreen as police inspect the vehicle
Nicky Hayden crash video: The Peugoet 207CC at the scene of the crash
Hayden, who has been racing for Red Bull Honda's World Superbike team, won the MotoGP championship in 2006.
"The young man, who is still in the intensive care unit of Cesena's Bufalini hospital, has suffered a serious polytrauma with subsequent serious cerebral damage," a hospital statement read.
"The prognosis remains reserved."
Who is Nicky Hayden?
Hayden is a 35-year-old motorbike rider who is nicknamed The Kentucky Kid.
His career high so far came in 2006 when he won his only MotoGP championship.
In the process he prevented Valentino Rossi from winning a sixth successive title.
Hayden was born in Owensboro in Kentucky and his talent was there for all to see early on.
At the age of just 17, he was racing factory Honda RC45 Sperbikes while still at school. It proved to be the first glimpse of his enormous talent.
Nicky Hayden crash pictures Fri, May 19, 2017
Nicky Hayden is in a serious condition after being involved in a road accident while cycling in Italy
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World Superbike champion Nicky Hayden is in a critical condition
Nicky Hayden crash video: A police officer inspects the footwell
He started his MotoGP career with Honda in 2003 immediately after winning the AMA Superbike championship. It was there, in his fourth year in 2006, that he won the title ahead of Valentino Rossi.
Hayden stayed for a couple more years before moving to Ducati in 2009 – and then back to Honda in 2014.
In 2016, he returned to the Superbike World Championship with the Ten Kate Racing-run Honda squad, now known as the Red Bull Honda World Superbike Team.
What happened to Nicky Hayden?
Hayden, 35, was cycling on the Rimini coastline in Italy on Wednesday. He was over there to race in the World Superbike championship on Sunday.
A road car crashed into his bicycle, knocking Hayden off and smashing the windscreen of the car in the process.
The Red Bull Honda rider received medical attention at the scene before being transferred to a nearby hospital for treatment.
How is Nicky Hayden now?
Hayden is in intensive care in Cesena. He reportedly has ‘severe brain damage’, a broken leg and pelvis.
Doctors are saying he is still too weak to be operated on.
"His condition is still extremely critical," a statement released by the hospital on Friday said.
"The prognosis stays reserved."
Follow live updates on Nicky Hayden here