The SmartWitness dashcam filmed the full bust-up, which started when the van driver overtook the grey Vauxhall Vectra and cut him up as they drove up a hill at 30mph close to Northampton town centre.
The manoeuvre enraged the Vectra driver who then accelerated and drove across the front of the van, causing a small collision.
The road rage driver, wearing a baseball cap, dashed from his vehicle and went to attack the van driver, banging on the door of his van so hard the vehicle shook.
A female friend travelling with him in the Vectra then got out and warned him that the incident is being captured on a dashcam clearly visible near the rear-view mirror at the front of the van.
The road rage driver calms down and a violent bust-up is averted.
CCTV supplier has released the footage after new figures were released showing a sharp rise in road rage incidents. Some police forces such as Devon & Cornwall have seen the number of incidents double in the last two years.
SmartWitness CEO Paul Singh said: “This new footage shows how a camera can be a fleet van driver's greatest friend following a road rage incident.
“It is amazing what a calming effect a running camera can have on a road rage driver intent on revenge. In this incident, the Vectra driver is alerted to the camera by a female passenger and he calms down after he had previously tried to break into the van's cab.
“Clearly the van should not have overtaken the Vectra and cut him up on such a busy town centre road. But that still does not excuse the violent reaction from the Vectra driver.
“Thankfully nothing more came of this incident but it does show the value of having a dashcam.”