Drunk Driving Reversal Casts Shadow Over Breath Tests

A state appellate court overturned the drunk driving conviction of an Orange County man Thursday in a decision that could help some defendants challenge the breath tests used against them.

The decision is so potentially troublesome to prosecutors seeking drunk-driving convictions that a top official of the Orange County district attorney’s office said the department is almost certain to appeal to the state Supreme Court.

The 4th District Court of Appeal in Santa Ana found that a lower court erred in blocking a jury from considering possible variations in the method used to find the blood-alcohol level of defendant Bruce R. McDonald.

At issue was a statistical ratio widely used in California to convert a driver’s breath-alcohol level into a blood-alcohol measurement, and thus to determine whether a person is legally intoxicated.

Constant Ratio Questioned

The state Administrative Code, backed by three recent rulings in Los Angeles Superior Court, maintains that a constant blood-to-breath ratio--an average of all people--should be used to determine if someone is too drunk to drive.

But defense attorneys have long maintained that the uniform blood-to-breath ratio is unreliable. The constant ratio, they say, fails to account for variations from person to person and variations within a single person over time, influenced by factors such as illness, medication and pollution.

Because many prosecutors around the state use the constant, inflexible ratio, “there are people getting convicted now who shouldn’t have been, who may not have been legally intoxicated,” said defense attorney Michael A. Garey of Santa Ana, who represented McDonald in his appeal.

Garey said the 4th District bench is the highest court so far to hold that juries must be allowed to consider variations in an individual’s blood-alcohol level.

Said defense attorney Garey: “This is an extremely significant case, because what it does is to protect and reinject a key element of fairness for the defendants in drunk driving cases.”

But Thomas M. Goethals, an Orange County deputy district attorney who handles the office’s appellate work, said he found the ruling confusing and “a bit disturbing.”

“I don’t think this will change the way we prosecute (drunk driving) cases yet, but it’s definitely a warning,” Goethels said. “This suggests a far greater latitude for defenses, and it gives more credibility and strength to attacks on the validity of breath tests, which has got to be troubling.

“This is an unusual opinion, and it has potentially very wide repercussions” for prosecutors around the state, Goethels said. As a result, he said, the district attorney’s office is likely to appeal the ruling to the state Supreme Court.

McDonald was stopped by a California Highway Patrol officer while driving erratically around 1:30 a.m. one night in October, 1986.

According to court records, McDonald smelled strongly of alcohol and his eyes were bloodshot, the officer reported. He admitted drinking five or six beers but said he was “OK to drive.”

McDonald agreed to take a breath test, and his blood-alcohol level registered 0.13. A driver is considered legally intoxicated in California when the blood-alcohol level reaches 0.10.

A 1980 study found that the breath-testing device used to check McDonald was accurate 85% of the time. Nonetheless, McDonald’s attorneys and a criminologist who testified in his behalf asserted that the ratio used to determine a defendant’s blood-alcohol level is faulty because it does not account for individual variations.

Rejecting that argument, a Superior Court judge instructed the jurors to assume that the standard blood-to-breath ratio applied to McDonald.

The appellate court criticized that instruction. The court found that the validity of the constant ratio “was in doubt. . . . Yet the court’s instruction effectively took that question from the jury and cast in stone a fact not proven.”