Gardaí are investigating a fight between a number of men on the M50 in Dublin.
The incident happened around 6.20 on Monday when two cars stopped on the motorway between the Redcow and Ballymount junctions.
Gardaí say a weapon was used by one of the men.
One man's been taken to Tallaght hospital where his injuries are not believed to be life threatening.
Another man was also injured but refused medical attention.
The altercation caused major delays on one of Dublin's busiest routes.
Gardaí have appealed to the drivers who may have dash cam footage of the incident to get in contact with them.