LOUISVILLE, Ky. (WHAS11) -- The connection between mother and daughter is everything, especially, for a daughter raised by a single mother.

“I had her my senior year in college. So, we kind of grew up together,” said Christa Hammack.

Hammack never went a day without hearing from her daughter, Erin Alexander.

“It was texting, or it was a call.”

Their last contact was Oaks Day 2018. As she headed to the track she received a text from Alexander.

“’Hope you have the best day and I love you,’” the text read. “And I said, ‘Thank you, I wish you were here.’”

Hammack was dressed up, enjoying her day in the Grandstand when, in an instant, the roar of the crowd muted as she tried to process the news.

“I got the call from her dad about an hour to post. I'm like, ‘What's going on?’ and he explains that there was an accident.”

A thousand miles away, on a wet four-lane highway about an hour outside Austin, Texas, a semi going the opposite direction lost control and crossed over the center line.

“The girls had nowhere to go, and they slid underneath and died instantly,” Hammack explained. Alexander was in the front passenger seat with her friend, 26-year old Jordan Hensley, who was driving.

“She was unviewable, which meant I couldn't touch her. Not her hands, not see her face. That she would be in a bag and you can't even see her. There was nothing to stop them.”

Alexander was only 22-years-old.

On the rear of a truck, a metal bar is required by law to help stop what are called "underrides." However, the sides of the truck are open, as Hammack said, with "nothing to stop them.”

“Could she have survived? Why do some people survive crashes and some not?”

That's the question Hammack will live with after seeing new safety tests for herself. In March, she traveled to Washington, D.C., to observe crash tests with and without technology designed to reduce the risk of underrides.

“The more I found out, the more frustrated I got,” Hammack said.

Tears quickly dry up when Hammack discusses the roadblocks to Senate Bill 665.

“There's not been a whole lot of anything but lip service on the cost-effectiveness or the undertaking that this would do to these trucks.”

The bill would require side underride guards on all new tractor-trailers over 10,000 pounds and require retrofitting to be done on trucks already on the road within two years.

The guards are not a new idea—they’re mandatory in Europe and Japan—but the United States continues to remain in the slow lane with the safety technology, even though the group Hammack has joined, Stop Underrides, says more than 4,000 people have died in underrides over the last 20 years.

While no one in the trucking industry would go on camera to answer our questions, the Owner-Operator Independent Drivers Association stated in an email that side and front underride guards would be a financial burden on small-business truckers and that the guards would make trucking challenging in certain places on the road and at loading docks. Read OOIDA's full statement here

Hammack says time is being wasted.

But more time may be needed following recommendations in a report from the Government Accountability Office.

“It says right here, ‘improve data collection, inspection, and research needed,’” Hammack read. “Do you think more research is needed? I think if you're going to make the best quality all the time, you never stop researching, but there's enough, there's enough proof, the data is there. We have done the tests, the engineers approved the tests, there are patents out there. I'm not sure what research they want.”

All four senators representing Kentucky and Indiana were too busy to go on camera, so we went across state lines for comment on side rail legislation to one of the sponsors of the bill, Senator Richard Blumenthal from Connecticut.

“Erin and Jordan might well be alive today,” Blumenthal said. “Literally hundreds of lives are lost because of the lack of underrail guards on the sides of trucks. They belong there, just as they're on the back now.”

Sen. Blumenthal says he's seen enough to vote in favor of the guards, which range in cost from $1,500 to $3,000. A cost which Blumenthal said is well worth it.

Clearly, the cost for Christa Hammack has been unbearable, even more so with every day that passes, even though for Alexander, mom is in it for the long haul.

“I think she'd expect that from me,” Hammack said. “Anyone who shares this road is at risk, that's why they should care.”

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