Johannesburg - A Johannesburg metro police patrol will be deployed to parts of the M2 highway at night after reports that criminals were placing rocks in the road to damage cars and target motorists, Chief Superintendent Wayne Minnaar says."We have heard about an incident that happened last night [Wednesday]. There have been incidents previously, but this is the first in a long time," he said.As the cars hit the rocks and people stopped their vehicles to inspect the damage, they were robbed by those who had placed the rocks.Alberton Record journalist Jacobus Myburgh told News24 he had hit a rock on the M2 just after the N3 highway ramp. He was returning from OR Tambo airport on Wednesday night."A rock, strategically placed in a plastic bag in the middle lane, caused some damage to my vehicle at about 23:00 last night [Wednesday] after returning from a late flight from Port Elizabeth," he said."As I just got on to the M2 freeway, I noticed something in the middle of the road. Obviously at that point, I was unable to swerve, as I was unsure whether there were other vehicles around me."He said he hoped it was just a plastic bag and he was forced to drive over it."I got out of the car to check, because I didn't know what it was. My mother, who came to pick me up, was checking the damage on the car."He said as he was about to warn other motorists, two other cars also drove over the rock in the packet. Those cars had also suffered damage as a result."Oil was leaking from underneath my car, so I think something to do with the oil was damaged."He said he eventually picked up the rock and drove away."As I did that, a guy who was lying on his stomach nearby, got up. He looked very angry that I took the rock," Myburgh said, adding he took the rock with him and drove away.He said while driving away, he spotted more than five motorists who were forced to pull over to inspect the damage to their vehicles.