Code of Federal Regulations Title 36. Parks, Forests, and Public Property § 36.3.11 When is testing for alcohol or drugs required?

(a) At the request or direction of an authorized person who has probable cause to believe that an operator of a vessel has violated provisions of § 3.10, the operator must submit to one or more testing procedures of the blood, breath, saliva or urine for the purpose of determining blood alcohol and/or drug content.

(b) The results of chemical or other quantitative tests are intended to supplement the elements of probable cause used as the basis for the arrest of an operator charged with a violation of § 3.10. If the alcohol concentration in the operator's blood or breath at the time of testing is less than alcohol concentrations specified in § 3.10(a)(2), this fact does not give rise to any presumption that the operator is or is not under the influence of alcohol.

(c) The provisions of paragraph (b) of this section are not intended to limit the introduction of any other competent evidence bearing upon the question of whether the operator, at the time of the alleged violation, was under the influence of alcohol, or a drug, or drugs, or any combination thereof.