To determine whether there has been a violation of the Fourth Amendment, courts must first analyze whether there has been a “search” or “seizure.” Current doctrine offers two methods of identifying a “search”: the trespassory test and the Katz test. Scholars have criticized the Katz test, which asks whether an individual has a reasonable expectation of privacy, as being difficult to apply. In Carpenter v. United States, Justice Gorsuch proposed discarding the current framework in favor of a new model. Under his suggested approach, an individual’s Fourth Amendment rights would be determined on the basis of their property rights (the “strict property test”). To test the feasibility of the proposal, this Note applies Justice Gorsuch’s framework to an issue that current doctrine appears to struggle with: Are downloads of Event Data Recorder (EDR) data Fourth Amendment searches? EDRs are computers installed in modern cars that record information on the vehicle’s operation, and state courts have split on whether law enforcement downloads of the data stored on these devices constitute Fourth Amendment searches. After examining the issue of EDR data downloads through the lens of the strict property test, this Note suggests that Fourth Amendment law would be better served by a series of minor doctrinal shifts rather than the substantial modification that Justice Gorsuch advocated for in Carpenter.

The full text of this Note can be found by clicking the PDF link to the left.


Ninety-nine percent of registered vehicles in the United States are equipped with a little-known device: an event data recorder (EDR). 1 Richard Ruth, Ruth Consulting, LLC, Presentation at the Symposium on Traffic Safety: EDR Update 2018, at 4 (May 21–24, 2018),
summit/handouts/Ruth%20R_2_EDR%20Update%202018.pdf [].
Usually embedded beneath the carpeting underneath the driver’s seat, 2 How to Preserve Your Car Black Box (Event Data Recorder), Collision Sci. (Dec. 1, 2014), [] (diagram depicting typical locations); see also Steven T. Kean, Va. State Police, Event Data Recorder: An Overview 6–7 (2015), [] (providing images to demonstrate the location of the ports through which the EDR module can be accessed). these devices continuously measure information on a car’s speed, braking, acceleration, angular momentum, and other similar data. 3 Federal regulations require that EDRs record at least fifteen data points. See 49 C.F.R. § 563.7(a) (2019). This informa­tion is generally not retained in permanent storage unless the car is in an accident, in which case the EDR will permanently save the data for the five seconds preceding the accident. 4 See Michelle V. Rafter, Decoding What’s in Your Car’s Black Box, Edmunds (July 22, 2014), []. The data is saved locally onto the EDR hard drive; these “black box” devices do not rely on cloud storage. See id. In the event of an accident, law enforce­ment can use data saved on an EDR to reconstruct the facts of the accident and support criminal cases brought by the state for charges such as invol­untary manslaughter or driving under the influence. 5 See, e.g., People v. Diaz, 153 Cal. Rptr. 3d 90, 96–97 (Ct. App. 2013) (describing the evidence obtained from an EDR and its use by police to determine the conduct of the defendant in the moments before a fatal automobile accident); Chavis v. Commonwealth, No. 1029-16-2, 2017 WL 3026772, at *1–2 (Va. Ct. App. July 18, 2017) (describing the prose­cution’s use of EDR data to establish the defendant’s speed in support of a charge of invol­un­tary manslaughter); Miller v. Commonwealth, No. 0193-16-2, 2017 WL 3026782, at *1–2 (Va. Ct. App. July 18, 2017) (describing the prosecution’s use of EDR data to establish that the defendant was not wearing a seatbelt at the time of a car accident and did not attempt to steer away from the accident to support a conviction for driving under the influence). To date, five state court systems—yielding six appellate court opinions—have ruled on what restraints the Fourth Amendment imposes on law enforcement efforts to obtain EDR data. 6 As of October 23, 2019, a Westlaw search querying <“event data recorder” & “Fourth Amendment”> for all federal and state courts, without any time limits, yields twenty cases, but only six of those opinions actually address the issue of Fourth Amendment limits on EDR data. See Diaz, 153 Cal. Rptr. 3d at 97–102; State v. Worsham, 227 So. 3d 602, 603–06 (Fla. Dist. Ct. App. 2017), cert. denied, 138 S. Ct. 264 (2017); Mobley v. State (Mobley I), 816 S.E.2d 769, 772–74 (Ga. Ct. App. 2018), rev’d, 834 S.E.2d 785 (Ga. 2019); State v. West, 548 S.W.3d 406, 414–18 (Mo. Ct. App. 2018); People v. Christmann, 776 N.Y.S.2d 437, 441–42 (Justice Ct. 2004). A sixth case, People v. Xinos, 121 Cal. Rptr. 3d 496, 506–13 (Ct. App. 2011), also analyzed EDR data downloads but was ordered not to be published. This Note focuses on the Fourth Amendment analyses of EDR data in appellate court opinions, as they offer more detailed explanations of relevant doctrinal points.

The opinions feature an astonishing degree of variation on the thresh­old question of whether the Fourth Amendment protects EDR data at all. 7 See infra sections II.A–.B. The Fourth Amendment limits the government’s ability to conduct a “search” or “seizure.” 8 U.S. Const. amend. IV. Thus, for the Fourth Amendment to protect EDR data, it must be a “search” to download EDR data. 9 Cf. Carpenter v. United States, 138 S. Ct. 2206, 2220–21 (2018) (finding that a “search” within the meaning of the Fourth Amendment had occurred when police obtained the defendant’s cell-site location information). Current doctrine provides two methods for determining if a search has occurred: the Katz test 10 See Katz v. United States, 389 U.S. 347, 361 (1967) (Harlan, J., concurring). and the trespassory test. 11 See United States v. Jones, 565 U.S. 400, 407–08 & n.5 (2012); see also Florida v. Jardines, 569 U.S. 1, 8–12 (2013) (finding that a search occurred because a law enforcement officer exceeded the confines of the implied license to enter private property and knock on the door of such property); Kyllo v. United States, 533 U.S. 27, 40 (2011) (holding that use of a thermal imaging device constituted a search because it would have required a physical intrusion to obtain the information revealed by the device at the time of the Founding). Applying this doctrine, two courts concluded that down­loading EDR data does not constitute a search. 12 See People v. Diaz, 153 Cal. Rptr. 3d 90, 97–103 (Ct. App. 2013); Mobley I, 816 S.E.2d 769, 774–75 (Ga. Ct. App. 2018). The other four courts to consider the issue came to the opposite conclusion but followed dramati­cally different analytical frameworks to arrive at their respective holdings. 13 State v. Worsham, 227 So. 3d 602, 608 (Fla. Dist. Ct. App. 2017) (concluding that the Fourth Amendment applied because the defendant had a reasonable expectation of privacy in the EDR data downloaded), cert. denied, 138 S. Ct. 264 (2017); Mobley v. State (Mobley II), 834 S.E.2d 785, 791–92 (Ga. 2019) (holding that an individual had standing to bring a Fourth Amendment challenge because law enforcement physically intruded into the relevant vehicle to download EDR data); State v. West, 548 S.W.3d 406, 421 (Mo. Ct. App. 2018) (same); People v. Christmann, 776 N.Y.S.2d 437, 441–42 (Justice Ct. 2004) (holding that the Fourth Amendment does protect EDR data, but that law enforcement does not need to obtain a warrant to access the data). The total of four opinions also excludes the trial court opinions in states where the case at issue was heard by an appellate court (i.e. Florida, Georgia, Missouri, and California).

The divergence in results highlights the difficulty in applying current Fourth Amendment doctrine in the digital age, and it draws particular atten­tion to three difficulties in the current doctrine: the subjectivity of the Katz test, the unpredictability of the Katz test, and the lack of clarity on the rela­tionship between the Katz test and the trespassory test. Many scholars have criticized the Katz test, seizing on the test’s “ambiguous meaning, . . . its unsuitability for judicial administration, and its potential circularity,” 14 William Baude & James Y. Stern, The Positive Law Model of the Fourth Amendment, 129 Harv. L. Rev. 1821, 1825 (2016). in addition to lamenting the subjective and unpredictable nature of the test. 15 These critiques, and others, have been extensively developed by Fourth Amendment scholars. See, e.g., Ronald J. Allen & Ross M. Rosenberg, The Fourth Amendment and the Limits of Theory: Local Versus General Theoretical Knowledge, 72 St. John’s L. Rev. 1149, 1149 (1998) (arguing that the Court’s Fourth Amendment doctrine “lacks coherence and predictability”); Anthony G. Amsterdam, Perspectives on the Fourth Amendment, 58 Minn. L. Rev. 349, 384 (1974) (criticizing the first prong of the Katz test as seemingly permitting the government to declare the boundaries of Fourth Amendment protection); Craig M. Bradley, Two Models of the Fourth Amendment, 83 Mich. L. Rev. 1468, 1468 (1985) (describing a significant lack of agreement among courts on cases involving the Fourth Amendment); Sherry F. Colb, What Is a Search? Two Conceptual Flaws in Fourth Amendment Doctrine and Some Hints of a Remedy, 55 Stan. L. Rev. 119, 121 (2002) (criticizing the Fourth Amendment doctrine defining the meaning of a “search” as “untenable”); Orin S. Kerr, An Equilibrium-Adjustment Theory of the Fourth Amendment, 125 Harv. L. Rev. 476, 479–82 (2011) (proposing an alternate theory to both explain existing Fourth Amendment cases and guide resolution of future cases after describing problems with the current outcomes and underlying theoretical framework); Donald R.C. Pongrace, Stereotypification of the Fourth Amendment’s Public/Private Distinction: An Opportunity for Clarity, 34 Am. U. L. Rev. 1191, 1208 (1985) (describing Fourth Amendment doctrine as being in a state of “theoretical chaos”); Richard A. Posner, The Uncertain Protection of Privacy by the Supreme Court, 1979 Sup. Ct. Rev. 173, 188–89 (criticizing the Supreme Court’s reasoning in policy spying cases as “absurd,” “circular,” and “threadbare”); Jed Rubenfeld, The End of Privacy, 61 Stan. L. Rev. 101, 103–04 (2008) (criticizing Fourth Amendment doctrine for its failure to acknowledge the nature of privacy interests that it seeks to protect); Silas J. Wasserstrom & Louis Michael Seidman, The Fourth Amendment as Constitutional Theory, 77 Geo. L.J. 19, 28–29 (1988) (describing the lack of coherent theoretical underpinnings for the Fourth Amendment). Drawing on such arguments, in his dissent in the recent case Carpenter v. United States, Justice Gorsuch proposed discarding the Katz test in favor of a strict reliance on property rights to determine what constitutes a search. 16 See 138 S. Ct. 2206, 2264–68 (2018) (Gorsuch, J., dissenting). Under this approach (which this Note refers to as the strict property test), courts would determine if a search occurred by “ask[ing] if a house, paper or effect” that the government sought to access is “yours under law.” 17 Id. at 2268. This Note analyzes whether the strict property test actually offers a less subjec­tive, more predictable alternative to current Fourth Amendment doctrine by applying the strict property test to the issue of EDR downloads.

Ultimately, this Note argues that the strict property test, as currently formulated, does not in fact offer a less subjective and more predictable frame­work for determining whether a Fourth Amendment search has occurred. Section I.A summarizes what an EDR is, how it works, and what it is used for. Next, section I.B.1 provides a review of the relevant current Fourth Amendment doctrine. Section I.B.2 describes the facts and holding of Carpenter and then explains the contours of Justice Gorsuch’s proposed strict property test. Section I.B.3 describes federal laws and regulations specifically governing EDR data, and section I.B.4 does the same at the state level. Section II.A describes the facts and holdings of the state court decisions that have addressed the application of the Fourth Amendment to EDRs, and section II.B details the rationales each court relied upon in reaching their respective decisions. Section II.C reviews the problems with current doctrine that are highlighted by the state court decisions. Section III.A then analyzes the issue of EDR data downloads under Justice Gorsuch’s proposed approach. Section III.B compares the strict property test analysis with analysis under current doctrine. Drawing on this comparative analysis, section III.B concludes that significant work remains to develop Justice Gorsuch’s strict property test as a superior alternative to the current frame­work, and it suggests a number of relatively minor doctrinal adjust­ments that can address the problems raised in section II.C.