ARLINGTON (CBSDFW.COM) – Five years after a crash involving two eight-wheelers claimed the lives of two sisters, family members are trying to change the law to save more lives.

AnnaLeah Karth, 17, and Mary Karth, 13, were headed to Arlington from North Carolina to celebrate their older sister’s wedding.

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Annaleah and Mary Karth

They were in the backseat of their mother’s car when a truck swerved and hit it, causing it to spin around and then forcing it backwards underneath a second truck.

Accident scene pictures show the car was left a mangled wreck; the roof over the girls’ heads appeared to have been ripped away.

“AnnaLeah died instantly. Mary had a stroke and died several days later at a Children’s Hospital in Georgia,” said their sister, Rebekah Chojnacki.

The family soon learned that tractor trailers in the United States are required to have a rear guard to prevent so called ‘underride’ crashes where passenger vehicles slip underneath larger trucks. In many cases, though, like in the Karths’ collision, they fail.

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deadly crash involving Karth sisters

“We don’t want to just say this a tragedy and there’s nothing we can do about it. There are solutions, and we want to help be the solution,” said Chojnacki.

The Insurance Institute for Highway Safety and the National Highway Traffic Safety Administration have proposed tougher standards for rear impact guards to prevent hundreds of deaths a year.

Frustrated by the lack of progress, the Karth family helped write legislation that would require these improved standards for rear guards and, for the first time, mandate side impact guards.

Crash safety video of rear impacts and side impacts show the difference that such measures could make.

“I remember feeling like I was being squeezed, and all this noise,” said Marianne Karth, the girls’ mother who was behind the wheel when they crashed. She has successfully lobbied Congress to win bipartisan support for the bill in both the Senate and the House of Representatives. It was introduced into a Senate committee over transportation in December, where it is currently awaiting a vote.

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Karth knows, though, the fight is not over yet. “Until we get enough support to get this bill passed, people will continue to die,” she said.