Samandeep Singh knew the brakes on his truck carrying a 13-tonne load were faulty.
But he still got behind the wheel, killing a Victorian police officer who was riding her motorbike to work in January 2017.
Singh was then so guilt-stricken he tattooed First Constable D'Arne De Leo's police number on his body.
He also tried to take his own life eight times after hearing the voice of a "demon".
This "debilitating combination" of grief, shame and remorse led two appeal judges at Victoria's Supreme Court to on Friday hand Singh a shorter sentence than was originally imposed.
"The enormity of Ms De Leo's death weighed heavily on him and he tattooed much of his upper body with references to her and to the collision," Justices Emilios Kyrou and Stephen McLeish said.
"The extreme psychiatric response ... demands a significant moderation in the sentence that might otherwise have been imposed."
Singh, 30, was in May jailed for up to four years after hitting Ms De Leo, 45, at a Wantirna intersection.
His truck wasn't roadworthy and he knew the rear brakes weren't working. The front brakes were also compromised because the vehicle was loaded incorrectly.
Singh used his exhaust and emergency brakes in an attempt to stop, but rolled down a hill and smashed into Ms De Leo's motorbike.
Justices Kyrou and McLeish re-sentenced Singh to three years in prison.
"It was very dangerous for (Singh) to continue driving a fully-laden truck after he realised its brakes were failing, and to continue doing so for some distance rather than to stop," they said.
He must now serve at least one year and nine months behind bars, down from a previous non-parole period of two years and four months.
Singh received his heavy vehicle licence after a one-day training course. The company he worked for, Ermes Transport, had a shoddy maintenance record.
He initially denied knowing the brakes didn't work properly, but pleaded guilty to dangerous driving causing death after his planned trial was repeatedly delayed.
The officer's partner of 13 years, Krisztina Toth, in May said she wanted Ms De Leo to be remembered as a "kind, loving, beautiful person".
Her father, Patrick, previously said he did not hate or want revenge on Singh, who will likely be deported to India upon his release from jail.
Australian Associated Press