Is it possible that I was intoxicated at the time I was tested, but not at the time I was driving? And, does this make a difference?

Shortly put, the answers are "yes" and "yes." Our law only provides that the crime of DWI occurs when a person has an alcohol concentration of .08 or more in his body (or has lost normal use of mental or physical faculties at that time) at the time he or she is driving. So, the timing of the particular test in question can present a significant problem for either the prosecution or the defense (depending upon the circumstances). This dilemma usually arises in connection with breath and/or blood tests administered approximately 45 minutes to 1 hour and 15 minutes after driving. In such delayed testing, absent other information about the number of alcoholic drinks consumed, the type of drinks consumed, and knowledge of when the drinks were consumed, a person's alcohol concentration at the time of driving may have been higher, lower or the same.

In order to link the test result to alcohol concentration at the time of driving the prosecution may attempt to present expert testimony. The process the "expert" uses to relate the test result back to the time of driving is known as retrograde extrapolation. Depending upon the facts in your case, Mr. Threadgill may use his knowledge regarding alcohol absorption, distribution, and elimination to have the State's extrapolation evidence excluded or to raise issues of reasonable doubt in connection with that evidence.