"Accelerator" (一方通行 (アクセラレータ) Akuserarēta?, lit. "One-Way Road") is the 13th episode of the Toaru Majutsu no Index anime series. It was first broadcasted on December 27, 2008, with the script written by Nishizono Satoru, the episode storyboarded by Komino Mashiko, and directed by Takashima Daisuke.