The sprint star tweeted a photo of a man after an incident near Chelmsford in Essex.
Cavendish, 27, who was riding with Russell Hampton and Rob Hayles, told The Sun the man came up behind them on a country lane, beeped his horn then overtook dangerously.
The Tour de France rider banged on the car roof as a warning, then the driver stopped and "turned right deliberately" into their path.
Cavendish tweeted: "HE'S threatening to call the police! We want him to."
He added: “He could have ended our careers or worse. He looks old and frail but he was angry, patronising and rude.”
It has been a rough few weeks for Britain's top cyclists on the public roads.
Last month Bradley Wiggins suffered broken ribs in a collision with a car close to his home in Lancashire, and GB head coach Shane Sutton sustained a fractured cheekbone and bleeding on the brain in a separate incident.
Cavendish himself was involved in an incident with a car while training in Italy.