Your Car Is Watching You


By: Clayton Carlson, Volume 102 Staff Member

Out of all the things that people own that could be spying on them, they seldom suspect their cars. If you have purchased your car within the past few years, however, it is more than likely that your car contains a “Black Box,” also known as an Event Data Recorder, that is doing just that.[1] Black Boxes in cars record a wide variety of data, including speed, acceleration, braking, and more.[2] In some cases, sensors in the car even record who is sitting in seats at any given time.[3] Though Black Boxes were originally placed in cars as part of the safety system, they have proven invaluable in insurance investigations, litigation, and criminal investigations for the wealth of data they provide.[4] Despite owning these Black Boxes the vast majority of people could never access the data they record. That would require a set of expensive and complex diagnostic tools, in addition to professional training, that most people have neither the time nor money to obtain.[5] The police, however, do have the tools and resources to take data from the Black Boxes in our cars, which now begs the question of whether they should have to get a warrant for it before they do so.

Upon the advent of the widespread use of the automobile, the Supreme Court was faced with the difficult decision of how to treat the Fourth Amendment. The Supreme Court ultimately decided that “the public is fully aware that it is accorded less privacy in its automobiles because of [a] compelling governmental need for regulation.”[6] The ultimate test for a Fourth Amendment warrantless search of an automobile ended up looking at a combination of the car’s mobility (or potential for mobility) and whether it was on a public road or place not regularly used for residential purposes.[7] When extending searches to containers within cars, the Supreme Court has held that the Fourth Amendment does not compel separate treatment for a search of a container within an automobile and the search of the automobile itself.[8] Outside of an automobile, however, the rules on container searches are significantly different. In United States v. Chadwick, the Supreme Court noted, among other things, that—absent ability to prove some other exception like exigency based on individual circumstances—searching a container like a footlocker someone had on their person generally required a warrant.[9] Searches of containers of data are another distinct and evolving area. In the context of cell phones, for instance, the Supreme Court has held that a warrant is required before the police can conduct a search.[10]

Jurisprudence on Black Boxes is far more scarce, with no decisions as yet issued by the Supreme Court. In a recent significant decision, the Florida Fourth District Court of Appeals decided in State v. Worsham that, in the absence of exigent circumstances, the downloading of data from a car’s Black Box required a warrant.[11] The majority reasoned that a Black Box in a car was analogous to other data storage devices like cell phones that courts have required a warrant to search.[12] The majority also reasoned that the defendant had a “reasonable expectation of privacy” with respect to the information on the Black Box in their car.[13] This is in contrast to a decision in a California court a few years prior that held that obtaining speed and braking data did not violate any reasonable expectation of privacy.[14]

Other courts have previously held that other warrant exceptions, like exigent circumstances[15] or consent,[16] will allow the search of a car’s Black Box by police. Courts have not, however, explicitly explored the applicability of the automobile exception in the context of a car’s Black Box and how that squares with rules regarding cell phones.[17] The dissent in Worsham makes a compelling argument that the warrant requirement should not attach to a Black Box in a car.[18] The dissent notes that Black Boxes contain a far smaller array of information than cell phones and at least in the case of Worsham, do not even contain any GPS information.[19] Also, interestingly, the dissent argues that because the Defendant likely did not know there was a Black Box in the car, it would be hard to “conclude that the Appellee sought to preserve [that] information as ‘private.’”[20]

The arguments of the dissent are compelling because they highlight the fact that treating Black Boxes like cell phones inaccurately conflates the type of data they contain. Black Boxes do not contain intimate personal details, but rather simply the details of the vehicle’s operation.[21] It follows more logically to treat Black Boxes the same way as other containers in a car and analyze them largely under the automobile exception. They have many of the same qualities that other containers in cars have, especially in terms of movability and destructibility of evidence.[22] The limitations in the automobile exception would protect the Fourth Amendment interests of civilians while maintaining law enforcement’s ability to adequately investigate accidents.[23] It thus makes more sense to treat Black Boxes like containers within cars rather than like cell phones, and thus not require a warrant for the retrieval of their information so long as it is within a situation where the automobile exception would apply.

The decision to treat Black Boxes like containers within cars rather than cell phones would provide for more clarity within the law. The majority decision in Worsham only risks muddling jurisprudence in an era where more and more things are electronic and record some kind of data. By choosing to apply the automobile exception to Black Boxes, a court would maintain clarity and protections against unreasonable searches and seizures while also recognizing that changing the form of a search does not always differently implicate the interests behind it. Thus, as other circuits consider Black Box cases and, eventually, the Supreme Court, they should consider whether or not electronic data truly changes any of the calculations with respect to the automobile exception or reasonable expectations of privacy. In the instance of Black Boxes within cars, it does not seem persuasive that it does. Thus, the police likely should not need a warrant to search a Black Box within a car so long as they have probable cause and other elements of the automobile exception are met.

Thank you to Minneapolis City Attorney Judd Gushwa for the discussion and ideas that inspired this article.

  1. Orin Kerr, The Fourth Amendment and Access to Automobile ‘Black Boxes,’ Wash. Post (Mar. 30, 2017), (noting that “[m]ost cars manufactured in the past three years come with event data recorders . . . .”).
  2. Martin Kaste, Yes, Your New Car Has A ‘Black Box.’ Where’s The Off Switch?, NPR (Mar. 20, 2017, 4:46 PM),
  3. Id.
  4. Id.
  5. Kim Komando, Your Car’s Hidden ‘Black Box’ and How to Keep It Private, USA Today (Dec. 26, 2014, 7:00 AM), (discussing how tools and software for a Crash Data Retrieval System require professional training to use and cost between $2000 and $20,000).
  6. California v. Carney, 471 U.S. 386, 392 (1985).
  7. See id. at 392–93; Chambers v. Maroney, 399 U.S. 42 (1970).
  8. California v. Acevedo, 500 U.S. 565 (1991) (noting that as long as you have probable cause to search a container within a car, and other automobile exception factors are present, there is no warrant required for the search of a container within a car).
  9. See United States v. Chadwick, 433 U.S. 1 (1977). Though Chadwick was ultimately abrogated by Acevedo in 1991 in respect to its ruling on container searches within cars, Acevedo did not abrogate the section on container searches outside of cars or while someone is walking down the street.
  10. See Riley v. California, 134 S.Ct. 2473 (2014) (holding that generally a warrant is required for a search of cellphone data because it contains more information than would even a full search of someone’s house; and the search is not justified by something like protection of an officer).
  11. State v. Worsham, 2017 WL 1175880, at *4 (Fla. Dist. Ct. App. Mar. 29, 2017), cert. denied, No 17-176, 2017 WL 3325025 (U.S. Oct. 2, 2017).
  12. Id. at *2.
  13. Id. at *1.
  14. People v. Diaz, 213 Cal. App. 4th 743, 757 (2013).
  15. See People v. Christmann, 3 Misc.3d 309, 315 (Justice Ct. 2004) (holding that an exigency existed that allowed warrantless search of a car’s Black Box at an accident scene, as data could be purposefully or accidentally destroyed if the car was moved from the scene on its own power).
  16. Kirsch v. State, 276 S.W.3d 579, 587–89 (Tex. App. Ct. 2008), aff’d, 306 S.W.3d 738 (Tex. Crim. App. Ct. 2010) (holding that a defendant giving broad consent to search a car allowed the police to search the Black Box contained within the car).
  17. Christmann, 3 Misc.3d 309, 315 (noting that the automobile exception could not apply here because the police did not have probable cause to believe that evidence of a crime was contained within the car).
  18. State v. Worsham, 2017 WL 1175880, at *5–8 (Fla. Dist. Ct. App. Mar. 29, 2017) (discussing how there should not be a reasonable expectation of privacy regarding events recorded by a Black Box).
  19. Id. at *6 (noting that cell phones are carried close to the body, whereas this is on the undercarriage of a car, and contains highly impersonal information “such as the vehicle’s yaw rate”).
  20. Id.
  21. Kaste, supra note 2.
  22. Christman, supra note 15.
  23. See also, supra notes 8–10.