The mayor of Rosetown is calling for twinning of Highway 7 after three members of a B.C. family were killed in a head-on crash.

Forty-seven-year-old Douglas Janzen, and his two daughters – 19 year old Allie, and 13 year old Cassidy, died in the crash Sunday.

Janzen's wife and son remain in hospital in Saskatoon.

RCMP say the Janzens' vehicle attempted to pass a truck during heavy rain. They slammed into an oncoming SUV, carrying two people from Plato, Saskatchewan, who also remain in hospital.

Rosetown Mayor Brian Gerow says there are too many accidents on the highway. He told CTV that between 2005 to 2010 there were 354 people injured on Highway 7, and 23 killed.

"It is a very dangerous stretch of highway," Gerow said.

RCMP say the tragedy reinforces the need for caution when driving.

"You have to be able to see," said Cpl. Rob King. "You have to be able to judge the distance between you and the oncoming traffic."

The province says it is working on a plan to improve the highway, but it will take time.

"Part of the analysis is looking at what portions of that would be twinned," said Ted Stobbs, Assistant Deputy Minister with Highways and Infraustructure. He says it could be a decade before the changes are made.

Meanwhile friends and neighbours in Sorrento, BC, grieve the losses, which have hit hard in the small community.

"They're connected to every facet of the community," said Rubin Pauls, with River of Life Church.

"Disbelief – that's the first word…..you say this can't happen here."