Proving Drunk Driving in Maryland

There are two ways adult drivers can be charged with drunk driving under Maryland law:

• Driving under the influence of alcohol or drunk driving “per se,” if your blood alcohol concentration (BAC) is more than .08%; or,
• Driving while impaired by alcohol, where your conduct, demeanor, and mannerisms give police probable cause to arrest you.

To obtain a criminal conviction, a prosecuting attorney must establish one of these two scenarios beyond a reasonable doubt. Therefore, issues of proof are critical in a DUI case. Prosecutors typically rely on three types of evidence to prove that you are guilty of driving drunk, but each has its weaknesses. You should rely on an experienced Maryland DUI attorney to handle your defense, but an overview of the three forms of proof should be useful.

• Performance on Field Sobriety Tests: The One-Legged Stand, Walk and Turn, and Horizontal Nystagmus tests are used by police to assess your physical capabilities and ability to respond to instructions. Based upon your performance, they may arrest you or may request you take a portable breathalyzer test. The results of field sobriety tests can be attacked on multiple grounds, so they may not be admissible in court. Weather, the physical conditions at the scene, your own medical issues, and other circumstances could mean this evidence can not be used against you.
• Police Reports: Officers make a record of their interactions in every encounter with a driver, but the information they include in a police report is subjective. The details are based on their own opinions, which are often biased or motivated by their drive to get a conviction. Credibility issues can taint police reports, so they are of limited value as evidence in court.
• Results of Chemical Tests: Police often use portable breathalyzer devices to get a preliminary BAC, but this evidence is not admissible against you. The technology is sketchy, providing extreme variances and a high potential for false results. However, an official chemical test – given after your arrest under specific test conditions – is usually viewed as powerful evidence in court.

Still, there are defense strategies available to dispute the results. Blood, breath, or urine tests measuring your BAC must strictly comply with state law. The devices must be properly maintained and regularly calibrated for the evidence to be admissible. A defense attorney can also attack the credentials of the individual who performed the tests, or the chain of custody for the samples as evidence.

Discuss Your Case with a Skilled Maryland DUI Defense Lawyer

Though this summary of evidence in a drunk driving case may be informative, it is no substitute for the experience and knowledge that a Maryland defense attorney brings to the table. A lawyer knows how to pinpoint and exploit weaknesses in the case against you, which could raise enough reasonable doubt to result in acquittal of DUI charges. For more information, please contact attorney William Mulroney. I represent clients in central Maryland, DC and throughout Baltimore County, and I look forward to working with you.