This song finds Hayley Williams singing about "the three of us" and "second chances." Spin magazine asked the vocalist how much of the Paramore album is autobiographical about the departure of founding members Josh and Zac Farro, resulting in them becoming a three-piece. She replied: "The entire album is autobiographical, but it's not all about the lineup changes or losing two band members. I didn't want to write another record about being in a band. Not everyone in the world is in a band, so people can't all relate to that. I really just wanted to write about the things that I felt. And while I think there are shades of those things in the songs - I can't really stray away from the things that I've been through, so obviously it shows up - none of the songs are actually about Zac and Josh leaving the band."
Williams added: "'Fast in My Car' is actually more about people who can't let go of our past, and the people who can't see outside of the big, fat shadow of Paramore's soap opera. It's about just wanting to be left alone enough to grow and move forward and just enjoy where we are."
Regarding the eponymous album title, Williams told AbsolutePunk: "It just wouldn't seem right to try and force a name when these songs hit us like lightning ... We called the record what it is. It's really us. I hope that that says something important to our fans."
Williams explained this is the story of the friendship between her and her two bandmates. She said: "We got to this place where it was like, 'Let's make it easy on ourselves by just being open and honest and having a good time hanging out as a band.' When I hear that song, I think about us all piling into a car and going out on the town."
Hayley Williams explained the background to the song to MTV News: "We were living in LA when we made the record," she said, "and we were writing it out there too, and one night, I had, like, a Honda Hybrid car, and we pile into it, and there's only two seats, and so Taylor [York's] laid out in the back of it; we're all trying to fit into it to go get sushi. And it felt like one of those nights, back in 2004, when were headed to our first shows, and we all just piled in to a station wagon with all our stuff. It felt like that again, and it felt so good, so I wanted to write a song about us getting away together. Piling up in a car and getting gone."