COUNTRY CLUB HILLS, Ill. (CBS) — A desperate family made a new push for answers Monday in the killing of a beloved U.S. postal worker on Interstate 57.

Just over a year ago, Tamara Clayton, 55, was the victim of a random shooting on the expressway – one of the most dangerous in Chicago.

As CBS 2’s Jermont Terry reported, there are plenty of billboards to grab your attention along I-57 near 161st Street. But Clayton’s family wants every driver to pay attention to one specific one.

“She did not deserve this at all,” said Clayton’s daughter, Jayla Shelton, “and none of these people that you’re innocently killing deserve this. So just put them down.”

Shelton lives in Florida. While more than 900 miles away, she is determined to keep fighting to find out who shot her mother as she drove down I-57 in February 2019.

“By putting the billboard back up, let people know that my family is not giving up the fight,” Shelton said.

The fight entails putting the pressure on the drivers who likely saw something that night.

“She was not just some person or some postal worker that got killed on the expressway,” Shelton said.

Clayton worked for the U.S. Post Office. The USPS has provided a $25,000 reward, and the billboard sits where investigators found her slumped over the wheel after the random interstate shooting.

“So having it right there is a constant reminder of you were there that day, and you really just need to say anything if you remember even the slightest detail,” Shelton said.

The case remained open as of Monday night. But Shelton said tips or calls have not been coming into Illinois State Police.

“She was the backbone of our entire family,” Shelton said.

And she fears if the assailant isn’t caught, the loved one of someone else will pop up on another billboard.

“Don’t get used to the violence. Stay jaded,” Shelton said. “Fight for this.”

The billboard will remain up for a full month. The family is paying out of pocket.