Two people are dead and two others, including an 8-year-old boy, are seriously injured in a crash on Highway 63 south of Fort McMurray, Alta.
"It wasn't a problem with the vehicle and it wasn't a problem with the road or anything like that," said Sgt. Kevin McGillivray with Boyle RCMP.
"The collision was caused by one of the drivers not adhering to the rules of the road."
McGillivray says one vehicle was hit while making a left turn onto the highway from Township Road 720, 1 kilometre north of Wandering River.
The 52-year-old woman turning onto the highway died at the scene and a boy in the vehicle was airlifted to the Stollery Children's Hospital in Edmonton.
A man, 28, in the other vehicle was also killed while the male driver, 26, was taken by ground ambulance to Lac La Biche with life-threatening-injuries.
He was later also flown to an Edmonton hospital.
RCMP says no other people were in the vehicles. Alcohol and speed are not thought to be factors in the crash.
Driver behaviour needs to change: resident
The fatal crash comes on the same day as a safety event in Fort McMurray, partially aimed at promoting highway safety.
There have been calls to twin Highway 63 for years, reaching a high point this year after a crash killed seven people not far from Wandering River.
The Alberta government has promised to fast-track twinning of the highway, and appointed Fort McMurray-Wood Buffalo MLA Mike Allen as special advisor on the project.
"The community is simply in awe and deeply saddened … by another tragedy on Highway 63," Allen said.
"We're moving forward as fast as we can."
Allen says the province has added better signage along the highway and is in the process of building two new passing lanes.
He says they're also extending six existing passing lanes and hope to twin half the highway by 2015.
Theresa Wells, a Fort McMurray blogger who has been vocal about the need to improve the highway, says the government response has been encouraging.
"I think we have made some progress, and I think it's been some pretty rapid progress," she said.
Wells says while twinning the highway is important, more needs to be done to change the behaviour of drivers.
She says it's still too early to tell if Sunday’s crash could have been prevented with highway improvements.