The easiest way for the State to prove impairment in a prosecution for impaired driving is by introducing the results of a test of the defendant’s breath. Such test results are admissible without the foundation that would otherwise be required for this kind of scientific evidence so long as the testing was carried out in accordance with statutory and administrative rules governing implied consent testing. G.S. 20-139.1(b). Because the rule allowing breath test results to be introduced into evidence is relied upon so often, I thought it might be helpful to review the admissibility rule and the requirements for such tests.