(a) Upon the trial of any criminal action, or preliminary proceeding in a criminal action, pursuant to Section 3602, the amount of alcohol in a person's blood at the time of the test as shown by chemical analysis of that person's blood, breath or urine shall give rise to the following presumptions affecting the burden of proof:
(1) If there was at that time less than 0.05 percent by weight of alcohol in the person's blood, it shall be presumed that the person was not under the influence of an alcoholic beverage at the time of the alleged offense.
(2) If there was at that time 0.05 percent or more but less than 0.10 percent by weight of alcohol in the person's blood, such fact shall not give rise to any presumption that the person was or was not under the influence of an alcoholic beverage, but such fact may be considered with other competent evidence in determining whether the person was under the influence of an alcoholic beverage at the time of the alleged offense.
(b) Percent by weight of alcohol in the blood shall be based upon grams of alcohol per 100 milliliters of blood.
(c) This Section shall not be construed as limiting the introduction of any other competent evidence bearing upon the question whether the person ingested any alcoholic beverage or was under the influence of an alcoholic beverage at the time of the alleged offense.
(Added by Ord. 399-82, App. 8/12/82)