Graphic: Truck driver caught on video in most horrific crash you'll ever see, walks free from jail - but why?

An Aussie truck driver who crushed eight vehicles in a horror smash in northern Sydney in 2014 has walked free after he was cleared of all charges - months after being jailed for at least three years.

Eight cars were crushed after a truck careened into them while they were waiting at a set of traffic lights in northern Sydney. Source: Nine

Sarmad Nisan was acquitted by the Court of Criminal Appeal this morning after Justice Monika Schmidt agreed with claims the crash was caused by - faulty brakes.

The truckie had been previously jailed for at least three years in April after a judge agreed Mr Nisan had ignored multiple speed signs and failed to slow down in the correct gear before the crash.

That conviction was overturned today, with Justice Schmidt labelling the conviction "absurd" and agreeing with the defence faulty brakes were to blame.

Mr Nisan was caught on video losing control of the fully-loaded truck, which careened into several cars waiting at a set of traffic lights, in the suburb of Dee Why in 2014.

Senior constable Amy Champion and her colleague were seriously injured in the accident.

"This collision with the truck stole the last few months I would ever have to spend with my mum before she lost her battle with cancer," the constable said during the trial.

"It is something I will never be able to forgive the driver for, taking this precious time away."