Us Code § 343 - Presumptions

Full text of Us Code United States Code § 343 — Presumptions, with citation guidance and answers to common questions.

§ 343. Presumptions

For purposes of this chapter—

(1) an individual with a blood alcohol content of .10 percent or more shall be presumed to be under the influence of alcohol; and

(2) an individual shall be presumed to be under the influence of drugs if the quantity of the drug in the system of the individual would be sufficient to impair the perception, mental processes, or motor functions of the average individual.

(Added Pub. L. 99–570, title I, §1971(a), Oct. 27, 1986, 100 Stat. 3207–59; amended Pub. L. 100–690, title VI, §6473(c), Nov. 18, 1988, 102 Stat. 4379.)


Editorial Notes

Amendments

1988—Par. (1). Pub. L. 100–690, §6473(c)(1), substituted ".10 percent" for ".10" and struck out "conclusively" after "shall be".

Par. (2). Pub. L. 100–690, §6473(c)(2), struck out "conclusively" after "shall be".

CHAPTER 18—CONGRESSIONAL, CABINET, AND SUPREME COURT ASSASSINATION, KIDNAPPING, AND ASSAULT

Sec.
351.
Congressional, Cabinet, and Supreme Court assassination, kidnapping, and assault; penalties.

        

Editorial Notes

Amendments

1994—Pub. L. 103–322, title XXXIII, §330021(1), Sept. 13, 1994, 108 Stat. 2150, which directed the amendment of this title "by striking 'kidnaping' each place it appears and inserting 'kidnapping' ", was executed by substituting "KIDNAPPING" for "KIDNAPING" in chapter heading, to reflect the probable intent of Congress.

Pub. L. 103–322, title XXXIII, §330021(1), Sept. 13, 1994, 108 Stat. 2150, substituted "kidnapping" for "kidnaping" in item 351.

1982—Pub. L. 97–285, §2(b), (c), Oct. 6, 1982, 96 Stat. 1219, substituted "CONGRESSIONAL, CABINET, AND SUPREME COURT ASSASSINATION, KIDNAPING, AND ASSAULT" for "CONGRESSIONAL ASSASSINATION, KIDNAPING, AND ASSAULT" as chapter heading and substituted "Congressional, Cabinet, and Supreme Court assassination, kidnaping, and assault: penalties" for "Congressional assassination, kidnaping, and assault; penalties" in item 351.

1971—Pub. L. 91–644, title IV, §15, Jan. 2, 1971, 84 Stat. 1891, added chapter 18 and item 351.

About This Section

18 U.S.C. § 343 is part of Title 18 of the United States Code. The United States Code is the official codification of federal statutes maintained by the Office of the Law Revision Counsel of the U.S. House of Representatives. Congress amends the Code through new public laws, which are eventually incorporated into the relevant title.

This section may be cited in legal writing as 18 U.S.C. § 343. For the most current official text, including any recent amendments, use the official source links below. Do not rely on this page as the sole authority for legal citation or litigation.

How to Read This Statute

Statutes are organized by title, chapter, section, and subsection. Pay attention to words like "shall," "may," "and," and "or," because they determine whether a requirement is mandatory or permissive and whether multiple conditions must all be met. Historical notes and amendments often appear at the end of a section.

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Sources

Source: official Us Code text · Last verified 2026-08-27

Frequently Asked Questions About Us Code § 343

What does United States Code § 343 cover?

Section 343 ("Presumptions") is part of the United States Code, the codified statutory law of Us Code. It sets out the legal rule or procedure described in the text above. Statutes are amended regularly, so always verify against the official source.

How do I cite Us Code § 343?

A common citation format is "United States Code § 343" (Us Code). Legal writing may require the code abbreviation, section number, and year or edition. Match the style required by your court, professor, or publisher.

Is this the official text of Us Code law?

No. This page is for research and education and may not include the most recent amendments. For official current law, check the Us Code official source linked on this page or consult a licensed Us Code attorney.

How does Us Code § 343 apply to my situation?

Statutes are interpreted in context, and application depends on your specific facts. Only a licensed attorney in Us Code can advise on how this section applies to you. Contact your state or local bar association for a referral.

Sources & Verification

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