ACT Policing is seeking witnesses to an incident which occurred on the Barton Highway on Saturday (August 23).
About 11am, a driver of a black Ford Falcon, with three passengers, was travelling northbound on the Barton Highway, Lyneham, when they observed a dark silver Holden Commodore travelling at speed and tailgating other cars.
As the Ford driver approached the Gungahlin Drive Bridge, the Commodore driver drove up behind them at speed before moving to the left. At this time the driver of the Commodore leant out the window with a large silver shifter, striking the rear passenger side window, causing it to shatter.
The Commodore was last seen driving northbound on Barton Highway towards Gundaroo Drive.
The offender is described as Caucasian in appearance, aged in his late 20s, with a medium build, short brown hair and a red beard. He was wearing black sunglasses and a black, short sleeve T-shirt.
Police are urging anyone who may have witnessed the incident or have any information to contact Crime Stoppers on 1800 333 000, or via www.act.crimestoppers.com.au. Information can be provided anonymously.