  Radios are essential for the operations of modern police departments, and
they function as both a collaborative communication technology and a
sociotechnical system. However, little prior research has examined their usage
or their connections to individual privacy and the role of race in policing,
two growing topics of concern in the US. As a case study, we examine the
Chicago Police Department's (CPD's) use of broadcast police communications
(BPC) to coordinate the activity of law enforcement officers (LEOs) in the
city. From a recently assembled archive of 80,775 hours of BPC associated with
CPD operations, we analyze text transcripts of radio transmissions broadcast
9:00 AM to 5:00 PM on August 10th, 2018 in one majority Black, one majority
white, and one majority Hispanic area of the city (24 hours of audio) to
explore three research questions: (1) Do BPC reflect reported racial
disparities in policing? (2) How and when is gender, race/ethnicity, and age
mentioned in BPC? (3) To what extent do BPC include sensitive information, and
who is put at most risk by this practice? (4) To what extent can large language
models (LLMs) heighten this risk? We explore the vocabulary and speech acts
used by police in BPC, comparing mentions of personal characteristics to local
demographics, the personal information shared over BPC, and the privacy
concerns that it poses. Analysis indicates (a) policing professionals in the
city of Chicago exhibit disproportionate attention to Black members of the
public regardless of context, (b) sociodemographic characteristics like gender,
race/ethnicity, and age are primarily mentioned in BPC about event information,
and (c) disproportionate attention introduces disproportionate privacy risks
for Black members of the public.
