More than 300 vehicles were damaged in the incident, according to NSW Police, who allege "the secondary locking handles on the trailer were not properly engaged".

Crews were called to the Hawkesbury River Bridge near Mooney Mooney, 58km north of Sydney, just before 7.20am ... Authorities closed all southbound lanes of the M1 and one of three northbound ...

Citybound lanes of the M1 Motorway north of Sydney are shut after a two-vehicle crash. A car and a truck collided on the Hawkesbury River Bridge around 7:30am on Thursday.