DUI Defenses

To be convicted of driving under the influence (DUI) or driving while intoxicated (DWI) in Virginia, the Commonwealth bears the burden of proving you are guilty beyond a reasonable doubt. In the criminal court process, you have the opportunity to defend yourself or to hire someone to represent you. Since the nuances of DUI/DWI cases are complex, we do suggest that you find and retain an experienced Roanoke DUI attorney to help navigate the process and build a successful defense.

We’ve included some common defenses that could be used in DUI cases to suppress the prosecution’s evidence or to prove your innocence.

Private Property

Virginia’s implied consent laws mean that by driving on its highways or in its waters, you consent to drug and alcohol testing within three hours of an alleged offense if arrested. A highway, as defined in Code Section 46.2-100, as a public access road or street used for vehicles and law enforcement purposes. However, if you were in a parking lot at the time of the offense (or on other private property), implied consent does not technically apply.

Cause for Stopping

A police officer can pull you over for erratic or unsafe driving. If the officer determines that there is probable cause that your unsafe driving was because you were intoxicated, then you could be charged with DUI. However, it’s possible that you were driving erratically due to the external physical or environmental conditions (e.g. weather, terrain, etc.). These details could certainly factor into a defense. Law enforcement cannot stop you without reasonable suspicion that something criminal or dangerous was afoot.

Field Sobriety Tests

Field sobriety tests are voluntary and you shouldn’t have been forced into taking one. If you were forced or ordered to take one, then the court may find that the field sobriety test violated your Fourth Amendment rights. If this is true, then any evidence related to the test may be suppressed at trial.

There are other reasons why field sobriety tests are suspect and could be called into question during defense:

• Test conditions. For walking tests (e.g. one leg stand, walk and turn), the ground should be flat and level without distractions or slipperiness. The tests may not be valid if extreme weather or safety conditions apply where it would have been difficult for you to concentrate.
• Physical health conditions. If you suffer from vertigo, inner ear issues, injuries, or other health problems that prevent you from balancing or walking with ease, the field sobriety tests might not be valid.

Also, if you are not a native English speaker and you are asked to perform any speech related tests, then the validity of the test could be called into question. The same goes if you have a speech impediment or an injury related to your mouth.

Preliminary Breath Tests (PBT)

PBTs are used to justify an arrest but cannot be used as proof of intoxication, and like most other equipment, they are prone to malfunction. In Virginia, law enforcement must use the standard brand and model of PBT, use and maintain it according to instructions, calibrate the PBT properly, and inform you of your right to see the results of your PBT.

PBTs are prone to radio frequency interference from police officers’ devices and the interference can create false readings on the PBT. If the screen has any interruption, shows varying results, or flickers at all, it could be experiencing interference. In addition, PBTs are typically temperate sensitive and operate best between 60-95º Fahrenheit – yet many law enforcement officers keep this equipment in their trunk where temperatures can reach extremes. Be sure to tell your attorney as much information as possible about your testing experience and results.

If the police failed to tell you that the PBT was voluntary and that you had a right to see the results, a PBT may not be used to establish probable cause and justify your arrest. Your defense attorney can challenge the law enforcement officer’s training in using the equipment or in the overall administration of a PBT.

Evidential Test Devices (ETD)

Depending on how they are used, ETDs can be faulty. They’re meant to monitor alcohol levels from your lungs, but if you’ve recently consumed alcohol, vomited, or burped, your test results might show a higher BAC result than is normal because the alcohol levels are higher in your stomach and in your mouth. In Virginia, police officers are supposed to observe you for 20 minutes before administering the breath test to ensure that you haven’t burped or vomited. Your test may be skewed if the administrator of the test failed to wait the 20 minutes or if you burped before the test was given.

Also, how strongly you blow into the ETD makes a difference in your results. If you were forced or ordered to blow harder into an ETD, your results could be in question. Alcohol in your lungs concentrates around the bottom, which is why they want you to blow harder.

The State must prove that you were under the influence of alcohol or drugs with a blood alcohol content of 0.08 or more at the time that you were driving in order for you to be convicted of a DUI. Because ETDs are issued later – up to three hours after the arrest – your blood alcohol content can change. Each person metabolizes and eliminates alcohol differently, and any discharge from vomit or burping can impact the results as well. An attorney with experience in assessing forensic evidence and evaluating the equipment used is critical.

Blood Tests

Blood tests are less commonly used as a test for DUI/DWI. They typically only apply to drug testing or people who are unable to give breath tests. Even though blood tests are considered a more accurate measure of BAC, they still come with a myriad of complications and areas for concern. Here are a few things that may bring the blood test into question:

• You were told to submit to a blood test prior to your arrest.
• The blood was not drawn by a physician, registered professional nurse, graduate lab technician, or other designated party by order of the court.
• The arm from which they drew blood wasn’t appropriately cleaned or prepared for blood drawing.
• The syringe wasn’t sterilized or wasn’t disposable.
• The vials of blood weren’t sealed.
• The vials of blood weren’t properly labeled and identified.