The project was largely the cause of ongoing tension between DeLonge and Blink-182 bandmate Mark Hoppus and influenced the band's following studio album, the more experimental Blink-182 (2003).

A European tour for Blink-182 in winter 2001 was delayed in the aftermath of the September 11 attacks, and rescheduled dates in early 2002 were also canceled due to DeLonge's back problems.

The roots for Box Car Racer began with DeLonge playing acoustic guitar during recording sessions for Blink-182's 2001 album Take Off Your Pants and Jacket and grew from there.

[2] According to DeLonge, the project wasn't "meant to be a real band," but rather "something to do in some spare time that was really only expected to be on the low list of the totem pole of priorities in my life, and just to have an experimental creative outlet.

[5] He eventually settled on Box Car Racer, which was actually the name of a band Barker was in just after high school with schoolmates Alex Barreto and James Lopez, that DeLonge liked.

While reading about the war, DeLonge was "freaked out" to learn that Fat Man, the atomic bomb that was detonated over Nagasaki, was dropped from the B-29 bomber Bockscar (commonly misspelled Boxcar).

[6] To complete the project he invited fellow guitarist David Kennedy, whom DeLonge had met in the San Diego music circuit years prior.

[3] Kennedy began in San Diego straight edge hardcore group Over My Dead Body, and had become good friends with DeLonge the summer prior to recording.

The two had chatted about bands, gigs and the underground scene, which sparked off more interest from DeLonge in exploring his more traditionally hardcore punk leanings.

[1][8] "When your back is killing you and you have to have surgery and all this stuff, it's just kind of hard to keep a focus on the happier times in your life," he said in an interview with MTV News.

"[1] Box Car Racer was recorded over the course of six weeks beginning in December 2001, primarily at Signature Sound in San Diego, California.

[10] According to journalist Joe Shooman, while Box Car Racer was "essentially an outlet for DeLonge's more esoteric leanings, it very quickly became obvious that this was an album destined for release," largely due to Blink-182's explosive popularity at the time.

"[10] "I don't think there was ever a doubt it was gonna be released — you have a project with two members of Blink-182 on it, it's pretty hard not to turn a profit on that," said engineer Sam Boukas.

"[10] The creation of the Box Car Racer side project would cause great division in Blink-182, mostly between DeLonge and bassist Mark Hoppus.

[14] DeLonge did not announce song titles at the band's debut performance at San Diego's Mira Mesa Epicentre, as they were unfinished ("Letters to God" was listed on the setlist as "Maybe I Don't").

In a review of the performance, MTV News writer Brian Wallace remarked that "For the most part, Kennedy and bassist Anthony Celestino were careful not to do anything — physically or musically — that would distract attention away from the band's pop-punk marquee players.

[16] The band played their final show in Detroit, Michigan on December 17, 2002, with DeLonge remarking that he would like to experiment more with Box Car Racer one day, "an every-other-year type thing.

[4]Unfinished material from Box Car Racer eventually became part of DeLonge's next band, Angels & Airwaves, and their debut studio album, We Don't Need to Whisper (2006).

[29] Box Car Racer was inspired by and is partly a tribute to bands DeLonge credits as an influence: Jawbox, Quicksand, Fugazi and Refused.

[9][13] Critics primarily labeled Box Car Racer as pop punk,[30][31][32] but with a few other genre categories being ascribed to the band.