The reckless youths were filmed during rush hour on Friday, deliberately riding slowly in front of cars and cycling directly into the path of oncoming traffic.
One driver swerves and avoids a teenager by inches and is heard beeping his horn frantically.
The man whose dashcam recorded the mindless behaviour told Hull Live the stunt was “stupid” and, had a crash happened, it could have been fatal.
He said: “We were just driving when all of a sudden about 30 to 40 of them all pulled out on their bikes. They were driving all over the road and gradually more of them kept joining in.
“It seems their main aim was just to try and cause a traffic jam or when a car came they would just ride in front of it. It looked like they were trying to cause an accident.
“One of them pulled out in front of a car and caused it to swerve, there was a child seat in the car too. They obviously just don’t care and are trying to cause an accident. They’re just stupid idiots.
“I’m hoping their parents see this video and speak to them about it, they’re not just likely to cause a crash but they’re also putting their own lives at risk.
“When that boy pulled in front of the car, it was literally one second away from hitting him at a speed of 30mph, he would have been killed.”
The footage, which was shared online, has since been handed to the police.
They say there has been a rise in antisocial behaviour in Bransholme, Hull, lately and they are increasing patrols in the area.
But social media users have suggested police intervention isn’t enough.
“Bring back borstal,” states one Facebook user.
“Out of control and have no respect,” writes another.
“Maybe police should step up more and take control back, country is a complete laughing stock,” a third posted.
Another shared: “Bring back National Service.”
Sergeant Stephen Hepworth, of Humberside Police’s Neighbourhood unit, said: “Unfortunately, we have noticed a rise in reports of antisocial behaviour committed by a small number of young people in the Bude Park area, Hull who believe it is acceptable to cause damage and disruption to our local community.
“Our parks, playing fields and other communal areas are there to be enjoyed by our communities. Antisocial behaviour is an issue we continue to tackle working in partnership with the local authority and secondary schools, it is totally unacceptable for public spaces to be damaged or littered.
“Throughout the course of the next couple of weeks, residents will see an increased presence from our dedicated local Neighbourhood Policing Team who are continuing to carry out patrols across hotspot areas taking positive action.
“Our officers will be highly visible and engaging with local residents, young people and their parents from across the area.
“We would appeal for our communities to report any instances of antisocial behaviour or criminal damage to us on our 101 number, and to keep up to date with the latest action we are taking by signing up to My Community Alert.
“It is important that you tell us about the issues in your local area as this informs our plans and allows us to take continue to take robust action against those committing offences.”