Same; tests for alcohol or drugs, use as evidence

In any criminal prosecution for violation of the laws of this state relating to operating or attempting to operate a vessel while under the influence of alcohol or drugs, or both, or the commission of manslaughter while under the influence of alcohol or drugs, or both, or in any prosecution for a violation of a city ordinance relating to the operation or attempted operation of a vessel while under the influence of alcohol or drugs, or both, evidence of the concentration of alcohol or drugs in the defendant's blood, urine, breath or other bodily substance may be admitted and shall give rise to the following: (a) If the alcohol concentration is less than .08, that fact may be considered with other competent evidence to determine if the defendant was under the influence of alcohol, or both alcohol and drugs. (b) If the alcohol concentration is .08 or more, it shall be prima facie evidence that the defendant was under the influence of alcohol to a degree that renders the person incapable of safely operating a vessel. (c) If there was present in the defendant's bodily substance any narcotic, hypnotic, somnifacient, stimulating or other drug which has the capacity to render the defendant incapable of safely operating a vessel, that fact may be considered to determine if the defendant was under the influence of drugs, or both alcohol and drugs, to a degree that renders the defendant incapable of safely operating a vessel.