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Cal. v. Trombetta

Supreme Court of the United States

April 18, 1984, Argued ; June 11, 1984, Decided

No. 83-305


 [*480]  [***417]  [**2529]    JUSTICE MARSHALL delivered the opinion of the Court.

 ] The Due Process Clause of the Fourteenth Amendment requires the State to disclose to criminal defendants favorable evidence that is material either to guilt or to punishment. United States v. Agurs, 427 U.S. 97  [**2530]  (1976); Brady v.  [*481]  Maryland, 373 U.S. 83 (1963). This case raises the question whether the Fourteenth Amendment also demands that the State preserve potentially exculpatory evidence on behalf of defendants. In particular, the question presented is whether the Due Process Clause requires law enforcement agencies to preserve breath samples of suspected drunken drivers in order for the results of breath-analysis tests to be admissible in criminal prosecutions.

The Omicron Intoxilyzer (Intoxilyzer) is a device used in California to measure the concentration of alcohol in the blood of motorists [****5]  suspected of driving while under the influence of intoxicating liquor. 2 The Intoxilyzer analyzes the suspect's breath. To operate the device, law enforcement officers follow these procedures:

"Prior to any test, the device is purged by pumping clean air through it until readings of 0.00 are obtained. The breath test requires a sample of 'alveolar' (deep lung) air; to assure that such a sample is obtained, the subject is required to blow air into the intoxilyzer at a constant pressure for a period of several seconds. A breath sample is captured in the intoxilyzer's chamber and infrared light is used to sense the alcohol level.  Two samples are taken, and the result of each is indicated on a printout card. The two tests must register within 0.02 of each other in order to be admissible in court. After each test, the chamber is purged with clean air and then  [*482]  checked for a reading of zero alcohol. The machine is calibrated weekly, and the calibration results, as well as a portion of the  [***418]  calibration samples, are available to the defendant." 142 Cal. App. 3d 138, 141-142, 190 Cal. Rptr. 319, 321 (1983) (citations omitted).

 [****6]  In unrelated incidents in 1980 and 1981, each of the respondents in this case was stopped on suspicion of drunken driving on California highways. Each respondent submitted to an Intoxilyzer test. 3 Each respondent registered a blood-alcohol concentration substantially higher than 0.10 percent. Under California law at that time, drivers with higher than 0.10 percent blood-alcohol concentrations were presumed to be intoxicated. Cal. Veh. Code Ann. § 23126(a)(3) (West 1971) (amended 1981). Respondents were all charged with driving while intoxicated in violation of Cal. Veh. Code Ann. § 23102 (West 1971) (amended 1981).

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467 U.S. 479 *; 104 S. Ct. 2528 **; 81 L. Ed. 2d 413 ***; 1984 U.S. LEXIS 103 ****; 52 U.S.L.W. 4744



Disposition:  142 Cal. App. 3d 138, 190 Cal. Rptr. 319, reversed and remanded.


Intoxilyzer, breath sample, tests, breath, preserved, exculpatory evidence, blood-alcohol, concentration, samples, cases, destroyed, criminal defendant, respondents', calibration, suppress, alcohol, machine, blood, witnesses, suspects, driving, drunken, air

Constitutional Law, Fundamental Rights, Procedural Due Process, Scope of Protection, Criminal Law & Procedure, Discovery & Inspection, Brady Materials, General Overview, Civil Procedure, Jurisdiction on Certiorari, Considerations Governing Review, State Court Decisions, Appeals, Appellate Jurisdiction, Certified Questions, Preliminary Proceedings, Pretrial Motions & Procedures, Suppression of Evidence, Evidence, Relevance, Preservation of Relevant Evidence, Exclusion & Preservation by Prosecutors, Defenses, Right to Present, Duty of Disclosure, Obstruction of Administration of Justice, Perjury, Elements, Discovery by Defendant, Informants, Entry of Pleas, Guilty Pleas, Government Privileges, Official Information Privilege, Informer Privilege, Business & Corporate Compliance, Types of Commercial Transactions, Negotiable Instruments, Transfer of Negotiable Instruments, Substantive Due Process, Scope, Scientific Evidence, Bodily Evidence, Sobriety Tests, Admissibility, Standards for Admissibility