The semi-truck with a trailer was travelling north bound on the Calder Freeway when it veered off the busy highway, plunging down an embankment and into a creek about 5.20am today.
Police were told the truck hit a safety barrier and concrete pillar at the Spring Creek Bridge in Malmsbury, causing the rig of the truck to crash down and crushing the cabin.
Video captured by 9News shows the front of the truck crunched up by the freak smash.
Paramedics were called to the crash about 5.30am, with rescue crews working to remove the trapped driver from the vehicle for more than two hours.
The driver, a 36-year-old man, was flown to the Royal Melbourne Hospital with non-life-threatening lower body injuries.
The northbound lanes of the Calder Freeway are expected to be closed all day while equipment is used to salvage the truck and a recovery operation is undertaken.
Motorists have been advised to use the Calder Highway through Malmsbury, Taradale and Elphinstone to the Pyrenees Highway, then rejoin the Calder Freeway.
Police are appealing for anyone who witnessed the collision, or anyone with dash cam footage to contact Crime Stoppers on 1800 333 000.