Across the globe, governments are implementing electronic vehicle registration programs capable of locating automobiles instantaneously. In order to understand the impact of such programs on contemporary governance, this article draws upon the extant literature on automobility, law and society and science and technology studies theory, and data collected from Mexico, where the government has been implementing the Public Registry of Vehicles (REPUVE). The central argument of the article rests on three concepts. First, the automobile has recurrently served as a disruptive technology in modern society, a technology whose adoption unsettles the social order by drawing users away from their usual modes of social interaction. In response, state authorities over the course of the twentieth century created a collection of legal rules, actors, and institutions designed to take hold of the wheel. By penetrating automobility with law, the state transformed the car into a legal enactment device, a technology whose operation pushes people to enact the law and, in so doing, constitutes the sociolegal order. In Mexico, a host of forces have conspired to weaken the state's hold on the wheel. The REPUVE promises to change this by “delegating” policing duties to radio-frequency identification stickers affixed to vehicles and scanners placed on roadways. Rather than enforcing the law through corruptible humans sanctioning irresponsible drivers, the REPUVE opens the possibility of doing so through a “surveillant assemblage” denying roadway access to suspicious vehicles. In the REPUVE then, the automobile passes from a legal enactment device, a technology whose operation pushes users to enact the law, to a legal prescription device, a technology whose operation requires them to do so. By demonstrating the role of vehicular regulation in the “mutual becoming” of society and technology, this study contributes to the growing research on the intersection of law and technology and provides a glimpse into the changing nature of legal power in the contemporary state.