The crash saw a Hazeldenes Chicken Farm truck plunge 20 metres down an embankment.

Police are asking anyone with information or dash cam footage to get in touch with investigators.

Investigators have been told a white Scania prime mover and trailer was travelling north bound on the Calder Freeway about 5.20am on January 13.

They were told the crash occurred when the truck veered from the road and struck a safety barrier and concrete pillar at the Spring Creek Bridge plunged off the bridge between the north and south bound lanes crushing the cabin.

The driver, a 36-year-old man, was trapped for over two hours before being freed and taken to hospital for treatment.

The Calder Freeway was closed for almost 36 hours as a results of the crash.

Anyone with information or dash cam footage should contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au