((a)) Any person subject to this chapter who—
((1)) operates or physically controls any vehicle, aircraft, or vessel in a reckless or wanton manner or while impaired by a substance described in (article 112a(b)), or
((2)) operates or is in actual physical control of any vehicle, aircraft, or vessel while drunk or when the alcohol concentration in the person’s blood or breath is equal to or exceeds the applicable limit under subsection (b),
((b))
((1)) For purposes of subsection (a), the applicable limit on the alcohol concentration in a person’s blood or breath is as follows:
((A)) In the case of the operation or control of a vehicle, aircraft, or vessel in the United States, such limit is the lesser of—
((i)) the blood alcohol content limit under the law of the State in which the conduct occurred, except as may be provided under paragraph (2) for conduct on a military installation that is in more than one State; or
((ii)) the blood alcohol content limit specified in paragraph (3).
((B)) In the case of the operation or control of a vehicle, aircraft, or vessel outside the United States, the applicable blood alcohol content limit is the blood alcohol content limit specified in paragraph (3) or such lower limit as the Secretary of Defense may by regulation prescribe.
((2)) In the case of a military installation that is in more than one State, if those States have different blood alcohol content limits under their respective State laws, the Secretary may select one such blood alcohol content limit to apply uniformly on that installation.
((3)) For purposes of paragraph (1), the blood alcohol content limit with respect to alcohol concentration in a person’s blood is 0.08 grams of alcohol per 100 milliliters of blood and with respect to alcohol concentration in a person’s breath is 0.08 grams of alcohol per 210 liters of breath, as shown by chemical analysis. The Secretary may by regulation prescribe limits that are lower than the limits specified in the preceding sentence, if such lower limits are based on scientific developments, as reflected in Federal law of general applicability.
((4)) In this subsection:
((A)) The term “blood alcohol content limit” means the amount of alcohol concentration in a person’s blood or breath at which operation or control of a vehicle, aircraft, or vessel is prohibited.
((B)) The term “United States” includes the District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, Guam, and American Samoa and the term “State” includes each of those jurisdictions.