But he took the corner faster than intended, skidding the truck into a tree.
Mr Goodman was stood down from work and asked to undergo a drug and alcohol test, which found cannabis in his system.
At a disciplinary meeting the next month, Mr Goodman said a specialist suggested he use cannabis to stave off the hereditary eye disease glaucoma, from which his father had started to go blind in his 60s.
He also said he last smoked cannabis four days before the crash.
Mr Goodman was not immediately available for comment today, but told the authority he had not admitted to regularly consuming cannabis.
But the authority disagreed, citing a recording of the disciplinary meeting that Mr Goodman himself had provided.
"I don't usually smoke it, I usually eat it as a way of consuming it," he was recorded as saying.
"It still goes into my system, yeah. I'm going to have to cease and get medical advice for treatment of the glaucoma instead."
Mr Goodman argued he should have been allowed to take another drug test and given a final written warning.
But the authority found it was legitimate for the company to have serious concerns over Mr Goodman's cannabis use, whether he was smoking or eating it, and his dismissal was justified.
Rooney Earthmoving sought damages for repairs to the front of the truck, citing negligence on Mr Goodman's part.
Mr Goodman said the truck's tyres were worn and the trailers brakes were soft, which contributed to the accident.
But the authority disagreed, finding fault in Mr Goodman's driving. It said he chose to overtake a tractor on a wet road while towing a 40 tonne load, when he was only 700m from his turnoff.
It ordered him to pay the cost of the repairs minus the GST.
