Two 16-year-old boys have been arrested after allegedly throwing rocks at cars on the Kwinana Freeway.
Around 11.30pm on Friday, police received reports that vehicles travelling north near Berrigan Drive in Cockburn Central were being hit by rocks being thrown from the western side of the carriageway.
A number of vehicles were damaged.
On one occasion, a rock smashed through the windscreen of a Toyota Camry, hitting a 55-year-old man, who was a front seat passenger, in the chest causing injuries.
He was taken by ambulance to Fiona Stanley Hospital with non-life threatening injuries.
Further investigation by police led them to believe that the rocks were being thrown over a fence set up near roadworks.
Police Dog Mako was deployed and located two boys hiding in a shed at a nearby residence in Cockburn.
Two 16-year-old boys are currently in custody assisting with inquiries.