A prison specializing in sentenced traffic offenders is presented as an innovative model for Japan and elsewhere because of its unique features. Ichihara Prison for Traffic Offenders was established as a governmental response to a traffic crisis. Its appearance and persistence are attributed to a combination of expanded criminalization and accommodation to the relative tolerance that is extended to traffic law transgressors in Japan. The article places the innovation within the context of Japan's culture and of Japanese criminal justice processing, which produces one of the lowest imprisonment rates among industrial societies.