Her own life shifted course during a single moment nine years ago.
"The truck driver hit us it spun this around so that we went backwards into the back of the tractor-trailer ahead of us," the Wake County resident recalled.
Karth reenacts the moment with a plastic car and truck. It's a story she's told many times since the crash sent her world spinning.
It was May 2013 and Karth was road-tripping with her three youngest children from North Carolina to Texas. It was supposed to be a weekend full of celebrations between multiple graduations and a wedding, but the Karths didn't make it to Texas.
"The rear underride guard on that tractor trailer came right off. The back of our car went under the trailer. AnnaLeah and Mary were sitting in the backseat," Karth said. "AnnaLeah died instantly and Mary a few days later from her injuries."
It was a tragedy made worse by the news Karth discovered afterward.
"Putting the pieces of our lives back together we discovered about underride, had never heard of it before, and learned that hundreds of people die every year from going under trucks," Karth said. "And that engineers have designed solutions, but the trucking industry has not put them on and the government federal government has not required them to do so."
She said the news that her daughters' deaths could have been prevented caused her anger and frustration but also sent her down a path to prevent future deaths.
An advocate for safety measures
In advocating for stronger rear underride guards, she quickly uncovered a multitude of other traffic safety issues.
In recent years, traffic fatalities have been increasing across the state. NCDOT reported 1.755 people died on North Carolina roadways in 2021; the highest number in five decades. The agency found much of the increase was caused by speeding, unbuckled seatbelts and distracted driving. Accidents involving pedestrians, cyclists, and work zones decreased.
The ABC11 Data Team analyzed crash data from NCDOT between 2012 and 2021 and found the most dangerous intersection in the state is I-85 between Statesville St. and Graham St. The spot is responsible for more than 20 serious and fatal crashes.
NC 143 at SR 1150 and SL-TN also accounted for around 20 serious and fatal crashes in the past decade.
Locally, the Triangle's most dangerous roads are right outside of downtown Raleigh. I-440 between Glenwood and Six Forks is the most dangerous stretch of road. The section was responsible for more than a dozen serious crashes, according to NCDOT data.
I-40 between Rock Quarry and Hammond Road and I-440 between Capital Boulevard. and Wake Forest Road ranked as other top dangerous spots.
"There are traumatic and violent deaths and so we can't accept them anymore. And the good thing is that a lot of committees and in North Carolina, our leaders and committee members are coming together and saying, 'We can't accept these anymore. We have to address this,'" said Elyse Keefe, a project coordinator at the UNC Injury Prevention Research Center.
She helps communities with an initiative called Vision Zero, a goal to eliminate traffic fatalities.
"Vision Zero represents a paradigm shift. And so it really is something different from the traditional road safety approaches, which are trying to change individual behaviors and put all that onus on drivers and road users. So it acknowledges that actually, we all have a responsibility. So the designers of our roads and our communities all have a responsibility to address these problem areas," Keefe said.
Rethinking road design
Part of this rethinking includes road design, involving both speed and even how the roads separate cars from walkers and bikers.
Raleigh, Durham, Apex, and Chapel Hill are part of a handful of municipalities across the state that has signed on to the initiative.
"We're seeing that communities are, you know, realizing that this is a public health crisis, that it's something that they want and need to address," Keefe said. She said measurable change is going to take some time as the initiative presses for systematic change.
Karth is also part of the national group called the Road to Zero Coalition.
"We may never get to zero but the point is moving towards that, you know, as much as humanly possible," she said.
Karth remains hopeful that things will change. Last year, Karth's advocacy paid off. The trillion-dollar federal infrastructure bill included a law that mandated trucks to add stronger rear guards and calls for more research to be conducted on how to prevent cars from going under trucks.
But her fight is not done yet.
"I can't imagine just letting it go and not trying to do something about it," she said.
Karth said the public has a role to play in reducing traffic fatalities and encourages everyone to help.
"It's not just trying to prevent the crash or just trying to reduce injuries from the crash; it's both, Karth said. "Do everything you can to both prevent the crash and make any crashes more survivable."