When faced with a traditional DUI charge, and the indicated level of alcohol allows the state to have a presumption of intoxication in its favor, the defendant must introduce evidence of non-intoxication to rebut the presumption, or face virtual certain conviction.
If the trial judge incorrectly instructs the jurors about presumptions (making it irrebuttable or mandatory), such instruction constitutes reversible error.
With blood tests, if the personnel drawing the blood for the state's test do not follow the required rules and regulations, the test results can be totally excluded from the evidence.
With blood tests, the use of an alcohol laden swab on subject's skin contaminates the puncture site and voids the test by the state.
The police lacked probable cause to make the "stop", so all tests and evidence gathered as part of the illegal arrest must be thrown out of court.
If the arresting officer misstates the required wording of the implied consent warnings, the state's BAC test results will be excluded from trial, or the entire case may be dismissed.
Use the "Driver's Rights" cards which "speak for you" in asserting your rights in the event of a confrontation with police.
"Blend in" with traffic because studies have shown that it is significantly more difficult for police to detect an impaired driver than when your car is isolated on the highway.
If the police fail to fully advise you of what types of independent tests you may take pursuant to state statutes and regulations, this will cause the state's test results to be excluded from evidence.
Proving that the defendant partition ratio is not "normal" such that the pre-set breath testing machine standards are inaccurate can provide the necessary evidence to convince the jury that the BAC results are not worthy of belief.
Proving that the defendant's hematocrit is outside the normal range and significantly "variant" to cause an adjustment in the indicated BAC reading may drop the defendant's BAC level below the per se standard (or the "presumed" intoxicated threshold) set by law.
Attacking the breath testing machine's accuracy based upon its record of failure during certification tests may cast sufficient doubt upon reliability of the machine to either cause the judge to exclude the test results or convince the jury not to believe the state's BAC reading.
Bridgework or false teeth may "trap" mouth alcohol and contaminate a breath machine sample. The failure of police to cause dentures to be removed before a test can be grounds for dismissal of charges, or at least grounds for excluding the state's breath test results.
Vomiting or burping delays the start of the breath test due to the contamination of your mouth by alcohol brought up from the stomach. The failure of the officer to restart the observation period will be grounds to exclude the state's BAC results.
Where the prosecution uses a witness to try to establish that you had a higher BAC at the time of driving (by using retrograde extrapolation techniques), based on the witness' lack of knowledge about your rate of elimination, timing of the drinking period, strength of the alcoholic beverage, and other variables which will affect the Widmark curve.
Always get the names, addresses and telephone numbers of potentially beneficial witnesses regarding your appearance of sobriety at the police station, or during the time your were receiving your independent tests. These witnesses may help your attorney build your defense.
When obtaining your independent tests, be certain that the laboratory analyzes whole blood and not plasma. Whenever plasma is tested, the results can be as much as 20% higher than when whole blood is utilized.
Always ask for "split" samples on blood tests so that an unaltered portion can be later tested to determine unusual hematocrit or other atypical conditions of your blood.
At the police station, stay seated and be certain that you maintain a composed demeanor at all times. You may be "on camera" with the police department's video tape machine.
If the police ask your permission to videotape you, don't agree to this, since this likely means that you look drunk, and they want to tape you so it can be used against you later.
Be certain that you can establish a "clean" chain of custody for your independent test samples in the event these are required to be transported for analysis.
Radio frequency interference may occur in police stations or in "mobile" testing facilities and may cause several brands of breath testing machines to give artificially high readings.
Whenever state law permits a preliminary hearing, the defense attorney may benefit from using this pretrial hearing to obtain sworn testimony from the witnesses for the prosecution which cannot later be changed or embellished to suit the needs of the state's case.
A defense attorney may use a motion in limine to suppress evidence to eliminate the state's principal evidence against you in the case (the BAC test result) thereby effectively winning the case.
A motion for disclosure under Brady v. Maryland will sometimes uncover potentially exculpatory evidence which will effectively negate the state's evidence.
Where the judge refuses to excuse a biased juror from the jury panel in your case, such refusal will constitute reversible error in the event you are convicted.
Once the state has put up all of its witnesses and evidence, and has "rested", the defense attorney can seek to have the judge decide that the evidence in the case is insufficient to support the defendant's conviction. This is called a motion for directed verdict of acquittal.