When Americans think of freedom, they often picture the open road. Yet nowhere are we more likely to encounter the long arm of the law than in our cars. Sarah Seo reveals how the rise of the automobile led us to accept—and expect—pervasive police power, a radical transformation with far-reaching consequences.

Before the twentieth century, most Americans rarely came into contact with police officers. But in a society dependent on cars, everyone—law-breaking and law-abiding alike—is subject to discretionary policing. Seo challenges prevailing interpretations of the Warren Court’s due process revolution and argues that the Supreme Court’s efforts to protect Americans did more to accommodate than limit police intervention. Policing the Open Road shows how the new procedures sanctioned discrimination by officers, and ultimately undermined the nation’s commitment to equal protection before the law.