321J.18 Other evidence. This chapter does not limit the introduction of any competent evidence bearing on the question of whether a person was under the influence of an alcoholic beverage or a controlled substance or other drug, including the results of chemical tests of specimens of blood, breath, or urine obtained more than two hours after the person was operating a motor vehicle. 86 Acts, ch 1220, §18; 98 Acts, ch 1138, §23
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