WASHINGTON — A landmark court case could change the way the trucking industry protects your family on the road.

WUSA9’s series of reports on deadly crashes known as “underride accidents” began in 2017. Now, the largest ever verdict against a trucking company for one of those underride accidents is exposing how the industry secretly fought new safety features for more than a decade -- despite knowing the risks.

A side underride accident killed 16-year-old Riley Hein on a New Mexico interstate in 2015. Riley’s car careened off an embankment and ended up lodged underneath the side of a trailer manufactured by Utility Manufacturing Company.

"The truck driver drug his car for a half a mile until it caught on fire and Riley burned to death," Riley’s father, Eric, said.

Riley Headstone
Headstone for 16-year-old Riley Hein who died in an underride accident in New Mexico in 2015.
Erin Hein

Eric Hein is now fighting for change.

In August, a New Mexico jury awarded the family a $42 million verdict in a lawsuit against the trucking company Barkandhi Express and Utility for negligence, for not having a side underride guard that could have kept Riley’s car from getting lodged underneath that trailer.

Side guards are designed to prevent vehicles from sliding underneath the side of an 18-wheeler in an accident. WUSA9 first spoke with Eric Hein at a crash test in March held outside Audi Field in Southwest D.C., where underride safety advocates had gathered to demonstrate how side guards work.

Right now, side guards are not required on trailers, despite the trucking industry acknowledging at trial that 202 people every year inside underride accidents.  

RELATED: 21 people dead from underride accidents in 2 months

But rather than including side guards on their trucks, internal documents that came to light during Riley’s case and that were obtained by WUSA9 revealed the trucking industry has been fighting the use of side guards for years.

A letter from the Truck Trailers Manufacturers Association asked all the major trailer manufacturers for data on the potential costs of side guards "to develop and evaluate possible defense strategies to side underride lawsuits."

WATCH: See footage from the underride crash ride test at Audi Field in March:

That survey was done in 2004, just one year after a trucking company in Texas was sued for negligence in a side underride accident. The jury awarded that victim’s family $36 million, the largest verdict in a side underride lawsuit -- until now.

"This is a tragedy that is entirely preventable," Hein said. "I don’t want any other families to suffer like we have."

After WUSA9’s series of reports “Big Rigs, Big Risks," U.S. Senator Kirsten Gillibrand introduced bipartisan legislation that would require those "underride guards" on the sides and front of semis as well as updating standards for underride guards on the back of trucks.

RELATED: Moms start online petition to 'end deadly underride' deaths

Rearguards are already required by law but often don’t hold up in accidents.

Two years later that legislation is stuck in committee. Truck safety advocates now believe huge judgments like the one in Riley’s case may be the only way to force change.

"These are the things that ultimately result in the eight-figure verdicts which can push a motor carrier into bankruptcy,"  Andy Young said, a former truck driver who now represents accident victims families in lawsuits against trucking companies.

"So, you’re actually protecting everyone in the industry as a result of these devices," Young said. 

The trucking company in Riley’s case is already out of business and won't have to pay its share of that massive judgment.

The trailer manufacturer, Utility Trailer Manufacturing Company, said it will appeal the nearly $19 million it was ordered to pay for its part of the judgment.

Eric Hein said the money isn't as important as the message that the trucking industry can be held responsible for underride deaths.

"He’d be proud of us," Eric Hein said of his son. "Yeah, he’d want us to go on. And we will."

Riley’s dad said the appeal to this verdict could take years, and that Utility offered the family a $14 million settlement that couldn't be appealed. But there was a catch -- the family had to keep everything, including those internal documents, quiet.

Riley’s father said they rejected that deal because it was more important to the family for the information uncovered in his son’s case go public.  

WUSA9 reached the Truck Trailer Manufacturers Association and the trucking manufacturer, Utility Trailer Manufacturing Company, for comment. Neither has responded.

RELATED: Big changes coming to big rig risks

READ: Full response from the Truck Trailer Manufacturer's Association 

RELATED: Government report says DOT has not done enough to study, stop truck underride accidents

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READ: Full lawsuit between the Hein family and Utility Trailer Manufacturing Company.