Under Michigan law, a motorist can be charged with Operating While Intoxicated (OWI) if the driver’s “ability to drive was substantially and materially affected by consumption of intoxicating liquor.” A driver can also be charged with OWI if chemical tests reveal a bodily alcohol content of .08 or more. Prior to 2004, the legal blood alcohol level was .10, but it was reduced under the new federally mandated .08 legislation. Meanwhile, a motorist can be charged with the lesser included offense of Operating While Visibly Impaired (OWVI) if the driver’s “ability to drive was so weakened or reduced by consumption of intoxicating liquor that [the motorist] drove with less ability than would an ordinary, careful and prudent driver. Such weakening or reduction of ability to drive must be visible to an ordinary, observant person.” People v Lambert, 395 Mich 296 (1975). For many years, if a motorist was over .07 but under .10, the driver was presumed to be impaired. This presumption was in addition to the element that the motorist “drove with less ability.” The prosecutor could introduce evidence of a breath or blood test of .08 or .09, and the judge would instruct the jury that the law presumed the driver was impaired. The accused could introduce other evidence to rebut the presumption, and the jury would consider that evidence in light of the legal instruction. When Michigan lowered the legal alcohol limit from .10 to .08, the Legislature removed the statutory presumptions for OWVI. The law regarding OWVI has reverted back to its original form, and there is no presumption that a motorist is impaired at any particular level. Many police and prosecutors immediately announced that a person could be charged with impaired driving at any level under the newly revised laws. This construction is true but misleading. The more aggressive jurisdictions construed this to mean that a driver was impaired at any measurable alcohol level, which is absurd. Without statutory presumptions, a seasoned drinker could be merely impaired at .18, far in excess of the legal .08 limit. Without a breath or blood test, another motorist could be found guilty of OWVI if there is enough evidence to prove that the driver consumed alcohol and drove with less ability than that of careful and prudent driver as a result of drinking alcoholic beverages. But could an inexperienced drinker who drives poorly be convicted of OWVI if a breath or blood test reveals a legal blood alcohol level? Conceivably, yes, but the blood test is not the relevant evidence used to prosecute that driver. The central issue in such as case is whether the inexperienced drinker drove poorly because of the alcohol. And this goes to the heart of the .08 debate. When the federal government decided to reduce the legal limit nationally to .08, they accomplished this by threatening to remove highway funds from the states. The federal government did this because there is a slight increase in the number of accidents above .05 that increases past .08 and above, even though the vast majority of drunk driving accidents statistically occur at .17 or higher. Historically, drunk driving prosecutions did not involve a breath or blood tests, and the issue for the jury was simply whether the evidence proved that the driver was drunk. Because alcohol is like any other drug and affects people differently, the widespread introduction of blood and breath testing raised an interesting question: At what level should we prohibit driving, even if the driver does not exhibit clear signs of intoxication? Lawmakers, with input from the American Medical Association, agreed that .15 should be used as a sort of cap. Thus, a person could be convicted of drunk driving if they were drunk or it was proven that the motorist was over .15 BAC. Over the years, the .15 legal limit was reduced by many states to .10 because it was too difficult for prosecutors to win cases when they had to prove that the driver was actually intoxicated. It has been widely acknowledged that most people exhibit few if any signs of intoxication at .08. According to one police manual, only 1 out of 5 drivers exhibit any sign of intoxication at .08, so police are required to put suspected motorists through a complicated series of difficult tasks. And this is being done because the federal government was concerned over the slight increase in accident rates that statistically appears over .05 and increasing past .08; it does nothing to address the real problem of drunk driving accidents that most frequently occur at .17 or greater. In light of the history of these legal presumptions, going back to our inexperienced drinker who is charged below the legal limit, what do the numerical results of a legal blood alcohol result mean in terms of prosecuting the motorist? What if the driver is charged at .07 or even .04? On the one hand, prosecutors are tempted to argue that .07 is close to .08, and jurors find this very appealing. As any five year old child can explain, 8 comes right after 7, but that does not mean that the driver was drunk or impaired. And if the inexperienced drinker’s BAC is measured at .04, which is clearly half the legal limit, it is equally irrelevant to the prosecution. Legal blood alcohol levels could be introduced as relevant evidence if the prosecution can explain what these readings mean through expert testimony, but the expert would be subject to cross-examination and have to answer difficult questions. More typically, these results will be introduced in some fashion by the defense as exculpatory evidence. Anyone can be charged with drunk driving, and several notable stories crop up each year where police officers arrest drivers who have no alcohol or drugs in their system. For the stone-cold sober motorist, those chemical tests tend to prove innocence, as does a chemical test reflecting a legal blood alcohol level for the responsible drinker.