Two people died Friday in a crash involving six vehicles on northern Alberta's infamous Highway 63.

Two semi-trailer trucks, two cars, one pickup truck and one van were involved in the collision outside the town of Boyle, about 150 kilometres north of Edmonton, on Friday morning, said the RCMP.

One male and one female died, while another person was airlifted by STARS air ambulance to an Edmonton hospital in serious condition. Four others were taken to the Boyle hospital with unknown injuries.

Highway 63 between the Athabasca Junction and the turnoff for Alberta-Pacific Forest Industries Inc. (Al-Pac), just south of Grassland, was closed as police investigated.

The names of the deceased are being withheld pending notification of family members.

People in the area have been lobbying for years to get the Highway 63, the main link between Edmonton and the oilsands, widened to four lanes.

Work to twin about 16 kilometres of the highway began in 2007.

There were more than 1,000 crashes on the highway between 2001 and 2005, killing 25 people and injuring 257 others.