More than three years have passed since Sheldon Baker's mother was killed when the ambulance she was travelling in went off the road as it was taking her home from the hospital.

An investigation was conducted but Baker says he and his family still have no idea how the crash happened and why his mother, 53-year-old Kim Lynette Baker, died.

He also says he can't get past the irony that a vehicle that is used to save lives took his mother's on September 17, 2008 near Hubbards, Nova Scotia.

"The doctor told her she was fine," he says. "The next morning on the way home in the ambulance, it left the road and she was killed on the site."

A few months after the crash, an RCMP officer visited the Baker family to explain the crash.

The RCMP said there was nothing wrong with the ambulance and the driver hadn't made any mistakes.

But they offered no answers as to why the vehicle left the smoothly paved road on a clear September morning.

"The investigators were able to determine that the vehicle had crossed the centre line but there was no conclusive factor as to why or how that turned out to be," says RCMP Const. Tammy Lobb.

The driver of the ambulance was fined $280 for driving to the left of the centre lane.

"The RCMP officer, Cpl. Christensen, said that maybe the sun was in the driver's eyes," explains Baker. "It was at 10:30 in the morning on the 103 Highway headed towards Bridgewater. Anybody in the world who ever drove that road knows that the sun is not going to be in your eyes."

But Baker has his own ideas about what may have happened that day.

"That he might have been on the telephone or texting with his wife," suggests Baker. "But we don't know that for sure either because we never received any kind of report to really saying anything other than the ambulance left the highway and your mother was killed."

The Baker family settled with Emergency Health Services for nearly $400,000 but Sheldon Baker says it's a settlement that was rushed due to his father's poor health.

He died six months later and the family is still waiting for $20,000, although Baker says it's not about the money.

"I want people to see that the system we're using is not right," he explains.

EHS wouldn't comment on the case, except to say they have co-operated with the RCMP's investigation.

With files from CTV Atlantic's Kayla Hounsell