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Having one more for the road may skew breath tests

In Virginia, it is illegal to operate a motor vehicle with a blood alcohol concentration of .08% or greater. For most adults, this can be as few as 2 or 3 drinks over the span of a couple hours. Click here for a website that estimates your BAC based on your weight, the number of drinks, and the amount of time.


Virginia police will ask you to perform a roadside sobriety test and then may ask you to take a breathalyzer. The breath test is designed to test the amount of alcohol in your bloodstream. But, if you’ve recently had a drink, the results of the test may be much higher than your actual BAC. This is because, during the absorption stage, your body’s alcohol level is not evenly distributed. This uneven distribution can create an inaccurate reading on the breathalyzer.


To measure alcohol using a breathalyzer, you have to blow through a tube. The breathalyzer works by mixing your breath with sulfuric acid, potassium dichromate, silver nitrate, and water. These chemicals mix with the alcohol in your breath and the breathalyzer creates a computer read-out that shows your BAC.


It can take your body up to 45 minutes to absorb your last drink. Even after your stomach has filtered the alcohol out to your bloodstream, it may still take some time for the alcohol in your blood to fully distribute (reach an equilibrium) across your entire body. The presence of food in your stomach may delay full absorption until up to two hours after your last drink. So, if you have that “one last drink” at the restaurant or bar before going home, you may be greatly increasing your risk that your breath test is higher than your true BAC, thereby greatly increasing your risk of a DUI.


Your first DUI conviction in Virginia is punishable by up to $2,500 in fines and up to a year in jail. Virginia requires all first offenders to attend an Alcohol Safety Action Program, commonly referred to as “ASAP,” which meets over a period of a few months. You will also lose your license for a mandatory period of one year. Finally, a DUI conviction will surely spike your car insurance rate.


There are many personal handheld breathalyzersavailable for purchase that may help you determine whether you should take a taxi home.




Michael S. Weisberg, P.C.
112 College Place
Norfolk, VA 23510
Phone: (757) 622-7740
Fax: (757) 533-9223
Toll Free: (800) 690-0235
Email: info@weislaw.com
www.weislaw.com