Three trucks were petrol-bombed on the N7 highway during the early hours of Tuesday morning.
According to Western Cape traffic chief Kenny Africa, a truck loaded with cement was petrol bombed and set alight just after midnight near Moorreesburg.
He said two vehicles forced the truck off the road and torched it. Minutes later, another truck was petrol bombed near the Porterville turn-off.
The driver was seriously injured. At 2am, a truck loaded with chicken was also set alight.