John Carpenter has acknowledged that La Nuit des morts-vivants (1968) was an influence on the marauding street gang. Like George A. Romero's zombies, they're completely dehumanized. They hardly talk and almost seem supernatural in their ongoing resilience.
Some of the gang members were played by USC students. They apparently had lots of fun finding ways of dying while spilling blood over themselves.
The assault takes place on Precinct 9, Division 13. Many have noted the title misnomer, since there is no "Precinct 13" in the film. At first, John Carpenter wanted to call the film "The Anderson Alamo" (the original title of his screenplay), and at one point he changed the working title to "The Siege", but no major studio wanted to distribute it. Irwin Yablans of Turtle Releasing Organization, a small distributor, saw the movie, loved it and promised to get it to the big screen, but rejected Carpenter's titles and came up with the name "Assault on Precinct 13" (which it felt was more ominous sounding) during post-production, and thus became responsible for the misnomer.
The story that Ethan Bishop (Austin Stoker) tells about his father sending him to a police station when he was six years old with a note is actually a true story told by Alfred Hitchcock about his childhood. Hitchcock detailed the story to François Truffaut in Truffaut's book "Hitchcock".
As a result of this film, Donald Pleasence would appear in such John Carpenter films as La Nuit des masques (1978), Prince of Darkness(1987) and New-York 1997 (1981), because his daughters were big fans of the movie.