Police are investigating after a rock was thrown at a car on the A12 in Ingatestone.
The victim was driving a red Fiat Punto under a bridge near the junction with the B1002 at 2.30pm on Saturday April 9 when he saw two teenage boys on the bridge.
They threw a large rock, which struck the windscreen, causing it to splinter on the driver s side.
The victim, a 52-year-old from Heybridge, was unhurt.
Officers carried out a search of the area and enquiries are ongoing to locate the suspects.
They were thought to be aged in their early teens, wore dark coloured clothes and had bicycles.
Witnesses or anyone with information are asked to contact police at Brentwood on 101.