A female driver allegedly made a gun sign at BBC presenter Jeremy Vine, after threatening to knock him down during an altercation with the cyclist on a narrow road, a court heard.
Shanique Syrena Pearson, 22, is said to have formed a weapon with her fingers and cocked it at Mr Vine's head as he pulled alongside her at a set of traffic lights, which he interpreted as a "serious threat", Hammersmith Magistrates' Court was told.
Pearson denies making the threat, claiming instead to have put her middle finger up at the presenter, who she thought was "a bit crazy" for following her after their initial row.
Mr Vine was forced to deny a suggestion by her lawyer that he was racially stereotyping the defendant by claiming she had formed a gun with her hand.
James O'Keeffe, defending, said: "I suggest to you that you have racially stereotyped her as a black person, and that gesture is associated with black people."
Mr Vine insisted he had just "told the truth", adding: "I saw very clearly what she meant with the gun gesture."
The alleged gesture followed a charged altercation between the pair, captured by Mr Vine, 51, on the helmet camera he wears for the commute from his home in Chiswick, west London, to BBC offices near Oxford Circus.
The clip of the row in Hornton Street in Kensington, west London, on August 26, was posted online by Mr Vine and has since been viewed millions of times, he said.
The presenter was cycling in the middle of the narrow road which had parked cars on either side, but stopped after being hooted at by the driver of a black Vauxhall Corsa behind.
In the clip played to the court, a high-pitched voice belonging to the female driver screams "Why would you do that?" while she gesticulates out of the car window.
A male voice, that of Mr Vine, can then be heard explaining that he needs a car's width between him and the parked cars to cycle safely on the narrow street.
Continuing, she says: "What the f***, why the f*** did you stop in front of my f****** car.
"Do you not respect your f****** life? Move your bike, move your bike," before allegedly kicking and pushing Mr Vine, and the cycle between them.
When she overtakes Mr Vine he is heard to say "oh my god, so scary", as she appears to pass close to a parked car.
A little while later, Pearson gets out of the Corsa a second time after noticing Mr Vine attempting to take a photo, and tells the presenter: "Take a picture of me again and I will knock you out."
As she advances towards Mr Vine he says: "Don't assault me, you've already assaulted me."
Mr Vine told the court of the next few moments: "She's gone back in the car, she's sitting at this junction. I am behind her with my cycle, the lights are red.
"I draw parallel to the car because I want to see inside.
"As I draw level and I look in she produces her fingers like this, and aims them at me, and cocks her thumb and goes like that, in a firing sign."
Dressed in a dark blue suit, the presenter, who went straight from his Radio 2 show to the court to give evidence, said his sole aim had been to calm the defendant down and he believed he was "dealing with a violent person".
He said: "I was actually quite scared about what was going to happen.
"I had to hold on to it (the bike) so my hands were down, so I had no real way of defending myself or even move away."
Pearson, of Vauxhall, south-west London, is charged with driving without reasonable consideration for other road users, and using threatening, abusive or insulting words or behaviour.
She has admitted to driving an unlicensed vehicle on the day in question.
Wearing a black top under a pale pink coat, Pearson sat in the dock as the footage was repeatedly played.
Giving evidence, she said she initially hooted to show Mr Vine she expected him to move over when the road widened, and performed an emergency stop when he then halted, adding: "It was too quick, it kind of shocked me."
The former assistant manager at a bookies accepted she had used bad language in the exchange, but said it was a bad habit she had picked up from her previous employment.
She then tried to push his bike out of the way, but Mr Vine held his ground, she said.
She told the court: "I know what I said was wrong and I am open to apology, but I think we both did wrong."
Continuing, she said: "I could have hit him (with the car) and I don't think he understood the danger of that, hence why I was so angry."
Mr O'Keeffe suggested Mr Vine had not abided by the Highway Code, by "stopping abruptly in front of a moving car".
"I believe I stopped not abruptly, not sharply, but safely," Mr Vine replied.
Asked why he did not move out of her way when the road widened, Mr Vine said guidelines advised against cyclists weaving in and out and that it was safer to hold a central course.
Mr O'Keeffe argued Pearson had not been upset about his central road position, but was "shocked and angry" because of how he had stopped in front of her.
Mr Vine said: "Maybe I was wrong to explain. I would not want to go through that again."
Asked if he had got the phone out to deliberately provoke her, Mr Vine replied: "How many people would get out of their car and threaten someone when they see a camera?"
Mr O'Keeffe said there was a credibility issue with Mr Vine's evidence, because he claimed to have been afraid but had acted in a way that was "utterly inconsistent" with fear.
The hearing was adjourned to January 26 when District Judge Timothy King will deliver a verdict at City of London Magistrates.