Barbara Briley and her great-granddaughter left Mays Landing, N.J., on the morning of Christmas Eve to drive to a family gathering in North Carolina, a trip Briley had taken many times before.

But Briley, 71, and La'Myra Briley, 5, never showed up.

Authorities Tuesday night were still trying to locate  the two. Barbara Briley was last heard from around 8 p.m. Christmas Eve, when she spoke to her son on the phone, according to her family. She said she was in standstill traffic near the split of Interstates 95 and 85, just south of Richmond, Va.

Hamilton Township Police did not return calls Tuesday, but they  told NJ.com that they had received a signal from Barbara Briley's phone in that area, and that they suspect she and La'Myra got lost.

But the family, who called 911 in the wee hours of Christmas Day after the two failed to show up in Morven, N.C., has grown increasingly concerned. They have scoured the highways for their missing loved ones.

"At this point, I really don't know what to think," said Terri Ramseur, 49, of Absecon, one of Barbara's three children. She said her mother, a deeply religious and kindhearted woman who is a former N.J. Transit bus driver, would call if she was lost. Or that La'Myra, who also lives in Mays Landing with family, would know how to use the phone.

Barbara's phone keeps going to voicemail, Ramseur said.

Her mother knows the route from her home in Atlantic County to North Carolina, she said.

"She could do it with her eyes closed," Ramseur said. "She's been doing it for years."

In the hours before they were last heard from, Barbara and La'Myra Briley stopped at an Exxon station in Ruther Glen, Va., more than 300 miles from their destination just southeast of Charlotte, N.C.

Barbara Briley said she missed a turn because of construction on the highway and couldn't get the GPS on her phone to work, according to Joanna Strange, a clerk at the station.

Strange said she helped Barbara Briley put in the address of her final destination, and then Briley and La'Myra left.

Strange said Tuesday she could not believe she was one of the last people to see the two.

"It's just so unreal," she said.

Family members visited the Exxon station Monday to search for clues, and a missing-persons flier was posted on the door.

"We're hoping and praying," said Tonya Floyd, 47, of Mays Landing, one of Barbara Briley's children. She said her mother does not have outstanding health issues.

Barbara Briley was driving a 2014 silver Toyota Rav 4 with New Jersey license plate C80-ELS.

Anyone with information can call Hamilton Township police at 609-625-2700.