Fairfax County, Virginia General District Court Judge Ian O'Flaherty has thrown out at least two cases that presumed a driver was intoxicated merely because his blood alcohol level was over 0.08 after being stopped. His ruling, delivered from the bench and not available in writing, found that Virginia law effectively presumed the automatic guilt of the defendant and was designed to ensure conviction. The law denies the ability of defendants to present scientific evidence that could suggest that some individuals are intoxicated at different blood alcohol levels and that one's blood alcohol content can rise as time passes. The judge believes this runs afoul of Francis v. Franklin, a 1985 Supreme Court ruling, that says all elements of a crime must be proven beyond a reasonable doubt.

The California Supreme Court, however, takes a different view and supports the very concept of designing laws to increase conviction rates. In 1994, the court ruled in People v. Bransford that California's DUI law, "will increase the likelihood of convicting such a driver, because the prosecution need not prove actual impairment... Adjudication of such criminal charges will also require fewer legal resources, because fewer legal issues will arise. And individuals prosecuted under such a statute will be less likely to contest the charges."

Prosecutors in Virginia are now avoiding taking any drunk driving cases to Judge O'Flaherty.

Patrick O'Connor, president of the northern Virginia chapter of Mothers Against Drunk Driving, said he was not aware of any other Virginia judges who have reached a similar conclusion. O'Flaherty's decision "undermines the efforts of the police and prosecutors to enforce the DWI laws, puts drunk drivers back behind the wheel and potentially denies justice to victims of drunk drivers," said O'Connor, who has requested a meeting with O'Flaherty. O'Flaherty, who has a reputation as a fairly tough judge among defense lawyers, turned down a request for an interview.