A memorial upgrade is taking place at the site of the Razorback Truck Blockade.
40 years ago truck drivers blocked the Hume Highway at Razorback Mountain to protest against road tax.
This was instigated by semi-trailer owner-driver Ted ''Greendog'' Stevens
In some instances drivers were sent to gaol for not paying the tax.
Mr. Stevens and a number of other truckies ended up blocking the Highway for nine days.
IMAGE CREDIT: Wollondilly Council