Police say the woman, whose name has not been released, left the Bradner Road rest stop at about 10:45 a.m. PT and started heading east in the westbound lanes of Highway 1.
She crashed head-on into a car with a young family inside, including a three-month-old baby.
The husband and wife sustained non-life threatening injuries, while the baby was not injured at all.
"This tragic loss of life has impacted a family forever," said RCMP Sgt. Peter Thiessen.
"This is a time of year when families come together and celebrate the holidays but unfortunately a family now grieves the loss of a beloved family member. Fortunately there was not a greater loss of life." The Upper Fraser Valley Traffic Services is investigating why the woman was driving in the wrong direction down the highway.