The pop star raised concerns Monday when photos surfaced of her driving her SUV in Malibu, holding her 4-month-old baby rather than putting him in a car seat as required by California law.
"I made a mistake and so it is what it is, I guess," Spears, 24, said in an interview with Access Hollywood that aired Thursday.
"It's the press. I mean, there is nothing new with them," she told Access, referring to constantly being followed by the media. "Being put in the situation that I was in, it was kind of bad with the paparazzi. Last week, my mom and I went out and they were on us really bad, so you instinctively do what you need to do."
In her statement to PEOPLE, Spears said she was "terrified that this time the physically aggressive paparazzi would put both me and my baby in danger.... I love my child and would do anything to protect him."
The Los Angeles County Sheriff's Department has said it won't pursue any charges against the star.