The New Jersey Supreme Court has become the first in the country to recognize a constitutional right to privacy in cell phone location records.
The court held earlier this month that that individuals have a reasonable expectation of privacy in their cell phone location data under the New Jersey state constitution.
In State v. Earls, the New Jersey high court found that "cell-phone location information, which users must provide to receive service, can reveal a great deal of personal information about an individual."
Consequently, law enforcement officers in New Jersey will be required to obtain a search warrant to track an individual's location.
In order to communicate with the telephone network, a cell phone must be in constant contact with nearby cell towers. These connections create a “paper trail” of an individual's phone records. By examining the location of towers to which a phone is connected over a period of time, law enforcement can track a person's movements in great detail.
In urban areas where cell phone towers are densely packed, a person's location can be pinpointed very precisely; tracking the phone is equivalent to tracking the person.
The decision in State v. Earls is the first state supreme-court case upholding location privacy since the U.S. Supreme Court’s 2012 decision in US v. Jones, a GPS tracking case. The state of Montana has passed a similar statute requiring warrants to track cell phone location.