The Mississippi Supreme Court has agreed to hear a driving under the influence (DUI) case that revolves around the theory of "retrograde extrapolation.''
Retrograde extrapolation is determining whether a person was drunk at a certain moment, based on results of a test given hours later.
The Supreme Court this past week agreed to review the case of Mary Reed Evans. The state Court of Appeals overturned Evans' conviction last November. The attorney general's office petitioned the Supreme Court to hear the case.
Evans was convicted in Monroe County Justice Court of first offense DUI. She lost an appeal to circuit court in 2007.
According to the court record, Evans drank four beers and ate at a Tupelo restaurant between 6 p.m. and 11 p.m. on July 19, 2006. She was stopped on the way home about 12:50 a.m. for DUI after a portable Intoxilyzer test. However, it was 1:58 a.m. before a blood alcohol test was given to her at the sheriff's department. She registered 0.09 percent -- over legal limit of 0.08 percent.
In circuit court, Evans wanted an expert to testify about retrograde extrapolation, but prosecutors opposed the move. The judge refused to allow the testimony.
The Court of Appeals ordered a new trial for Evans in which she would be allowed to pursue the retrograde extrapolation argument.
Evans' attorney, Josh Stevens of West Point, has said that to be driving while intoxicated, the key point is not when the test is taken but what the BAC was when a motorist was driving.
Stevens said any time there is lag from the time a motorist is stopped to the time they take the test, there is a question that arises about the BAC result.
In Evans' case, a chemical test at the sheriff's department only proved that Evans was legally intoxicated at the sheriff's department, according to court documents.
Evans claimed that her expert would show that from the time she was stopped by law enforcement officers until the time of the blood alcohol test, Evans' BAC was rising. It would have been lower if the test were taken earlier, she contends.
DUI attorneys have said Mississippi is an "at-the-time-of-driving'' state.
"One of those things that comes up in every case when you've got an extended time from the time of driving until the time of test ... there's always going to a question of, 'Well, officer, without guessing or speculating can you tell me what that person's breath alcohol content would have been back at the time of driving?''' said Jackson attorney Vic Carmody, who handles DUI cases but was not involved in Evans' appeal.
Some states have laws that say that, unless a defendant can prove otherwise, the BAC result at the sheriff's office will be assumed to be the same as it was when driving.
In Texas, the courts in 2003 held that breath-test results were admissible in court without "retrograde extrapolation'' analysis to determine blood-alcohol level at the precise moment a driver is pulled over.
In Idaho, a divided Supreme Court in 1999 ruled a motorist's blood-alcohol level at the time of testing is the one that counts, and cannot be extrapolated to conclude someone had earlier been driving drunk.
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