A drink-driver hit a pedestrian with such force one of the victim's shoes was found 40m from the impact site, a court has heard.

The man sustained a broken leg, an ankle fracture in three places and such severe concussion that he had no memory of the July 23 incident.

Matthew Dunbar, 28, clearly could have killed the man, Judge Dominic Flatley told the Dunedin District Court this week.

"This could've been much worse. You're extremely lucky that it wasn't.

"You're getting one chance here," he said.

Dunbar had been driving through Mosgiel, in Gladstone Rd North, following a drinking session.

Despite the temporary speed limit of 30kmh, because of roadworks, the defendant was doing well over 50kmh, witnesses said.

They reported seeing Dunbar overtake two vehicles, heading north towards Wingatui, before entering a corner on a raised berm.

He span out of control, over the opposite lane and into the pedestrian.

"The victim was propelled approximately 25m along the roadside, coming to rest in a ditch," court documents said.

Dunbar careened into a fence and his Subaru came to a rest facing south.

An evidential test gave a breath-alcohol reading of 706mcg.

Despite being nearly three times the legal limit, the defendant claimed he had only consumed three beers before getting behind the wheel.

The case left Judge Flatley exasperated.

"Every day, you pick up the paper and read about a person killed by a vehicle for no good reason.

"What makes it worse is you'd been drinking," he said.

"There are too many motor-vehicle accidents involving alcohol, I just don't know what needs to be done for people to stop."

The judge was somewhat comforted to see Dunbar looking uncomfortable in the dock.

"I can see from the way you're presenting, you're not enjoying this experience at all.

"You're finding it very stressful, and that a good thing, because you should."

Counsel Anne Stevens QC said that since the crash, her client had "made every effort to turn things around".

He had attended specialist addiction services, repaired the fence and apologised to the victim and accumulated $7500 for him.

The judge recognised Dunbar had an extensive support network of friends, family and work colleagues.

The defendant was sentenced to three months' community detention, 12 months' intensive supervision and 250 hours' community work.

Dunbar was also banned from driving for a year and a day.