The mother of a nine-year-old girl killed with her three-year-old cousin in a Coquitlam crash last April is suing the city, the transit authority and the province to demand road safety improvements.

Ella, 9, and Tyler Mollie Wong Hernandez, 3, died in a Lougheed Highway crash along with a 30-year-old woman who was in another vehicle on April 28.

Michelle Hernandez has filed a civil lawsuit in B.C. Supreme Court that names two drivers, the City of Coquitlam, the South Coast B.C. Transportation Authority and the province as defendants.

It says a failed attempt by one driver to pass on the highway near Pitt River Road sent two vehicles in to oncoming traffic.

The impact killed the two girls, who were passengers in a Nissan, and the other woman.

The lawsuit alleges that two drivers involved in the fatal crash failed to take proper care while driving.

The other focus in the statement of claim is road safety, which has been a campaign of Ella's parents, Michelle and Gary, since her death.

The couple has requested meetings with city staff trying to force officials to fix a section of road feared too narrow.

"Michelle and Gary [Hernandez] are really focused on trying to make sure this doesn't happen again," said Stephen Bruyneel, the family spokesperson.

"It would be a safety legacy for Ella if changes could be made," he told CBC on Wednesday.

Gary and Michelle Hernandez smiling with their daughter, Sophia. (Gary Hernandez/Facebook)

The lawsuit says the three deaths were caused by allegedly negligent drivers and other parties whom the civil filing claims at least contributed to the tragedy.

Court documents claim that "Coquitlam, TransLink and the province knew that the section of the Lougheed Highway where the collision occurred was poorly designed, dangerous and in need of safety barriers, re-engineering and construction," the notice of civil claim says.

Road too narrow

After the accident, Coquitlam Mayor Richard Stewart told CBC there are engineering challenges to making that section of highway safer.

CP Rail tracks on one side and a huge retaining wall along the Riverview Hospital lands restrict the city's ability to widen the road.

"We've asked our engineers to contemplate how we could do it ... put a barrier down the middle — but there's simply not enough roadway to accommodate a barrier," Stewart told CBC earlier this year.

None of the allegations in Hernandez's civil suit have been proven in court, and the defendants have not yet filed a response. Coquitlam RCMP continue to investigate the causes of the accident, but have no final report yet.

Since the accident there's been strong community support for the family, with $78,000 raised on a crowdfunding site for Ella's parents, both of whom are teachers.

"They are still in the grieving process. It's still a very difficult time," said Bruyneel, speaking for Ella's parents.

Tyler Mollie Wong Hernandez, 3, and Ella Reese Hernandez, 9, died in a tragic crash in April. (YouCaring)