Carol-Ann Berner was found guilty after Alexa Middelaer was killed and her aunt was severely injured when they were run down by a car while feeding a horse on a rural road.
In November 2010, Berner was sentenced to two and a half years in prison and banned from driving for five years, but appealed.
In its decision issued Tuesday, the B.C. Court of Appeal said the trial judge considered the results of Berner's breathalyzer tests and the expert evidence of the RCMP's forensic alcohol specialist in ruling the woman's ability to drive was impaired by alcohol.
Berner appealed on several grounds, including that the Insurance Corp. of B.C. disposed of her car before she was charged and the police accident reconstructionist made errors in measuring and analysis.
The trial heard undercover officers befriended Berner during a two-month sting and that she admitted to lying to police about drinking two glasses of wine, not three, and said she may have stepped on the gas pedal instead of the brake.