Executive Summary
Cell phones are ubiquitous. As of 2017, there were more cell phones than people in the United States. Nearly 70 percent of those were smartphones, with 94 percent of millennials carrying a smart device. Cell phones go nearly everywhere, and users are increasingly dependent on smartphone applications for daily activities, such as texting, email, and location-assisted direction services.
Cellular technology also allows service providers to collect a wealth of information about a user’s whereabouts. Cellular service providers automatically record the location of cell phones at regular intervals, transforming them into personal tracking devices. One court described them as the “easiest means to gather the most comprehensive data about a person’s public — and private — movements.” Cell phone location data is collected in such high volume that it offers a nearly inexhaustible source of granular information, including when and where someone goes, with whom, and even for what purpose.
This white paper surveys the landscape of government acquisition of location data about cell phone users — from cellular providers’ collection of location information to the use of technologies that pinpoint where individuals and cell phones are located. It describes how cell phones operate, how that location information is accrued and disseminated, and the technologies that can be used to establish where a phone is, where it has been, and what other users have been in proximity.
The paper then analyzes both the legal and policy landscape: how courts have ruled on these issues, how they can be expected to rule in the future, and how agencies have addressed these issues internally, if at all. It adds to concerns that cell phone-based monitoring could violate the constitutional privacy rights of millions of ordinary Americans — and that people of color are disproportionally affected. Finally, it concludes with a set of recommendations to enhance transparency and accountability around the use of cell phone location data and to ensure constitutional protections for users who are affected.