In order to pull you over for suspicion of Driving While Intoxicated (or a related offense), a police officer must first have “probable cause”. Probable cause is roughly defined as reasonable grounds for making a search. An individual’s driving is used to determine probable cause. For example, if someone is weaving through multiple lanes of traffic, that would be enough for a police officer to pull them over for suspicion of DWI. At times, a defense attorney can establish that the officer arrested the driver with no probable cause, or that the “cause” stated by the officer was really a pre-text for an illegal stop.
Your physical appearance plays a big role in the DWI arrest process. The arresting officer will testify that he/she believed you were under the influence of alcohol and/or drugs because you displayed any number of symptoms, including: slurred speech, blood shot eyes, smell of alcohol, incoherent speech, poor motor skills, etc. A DWI attorney will be quick to point out that non-intoxicated individuals can also display similar symptoms for innocuous reasons. For example, an individu might have blood shot eyes due to allergies or fatigue, or poor motor skills may be a result of a disability, recent surgery, etc.
When an officer suspects that a driver is intoxicated, they will likely ask the driver to perform one or more field sobriety tests. Field sobriety tests are used to test an individual’s motor skills and ability to properly follow instructions. These tests are indicators of driving impaired or intoxicated; they are NOT unquestionable proof. Even the most reliable field sobriety tests are only between 65-77% accurate in detecting if a driver is intoxicated. Field sobriety tests are typically given in a less than optimal environment, often a poorly lit roadside, or a road where the ground has cracks or is not level. An experienced defense attorney will point out to the jury that many of them (jurors) would have similar difficulties performing a field sobriety test under less than optimal conditions.
A breathalyzer is a device for estimating Blood Alcohol Content (BAC) from a breath sample. An experienced DWI defense attorney will explore all of the facts surrounding the method in which the BAC was obtained, and will focus not only on the device itself (ie, whether it was properly tested, properly cleaned, properly maintained, properly used, etc.), but will also focus on the person or persons who used the device, to make sure that any/all required certifications were in place, to make sure they were properly trained, and whether such person followed their training.
Another issue with the technology is that a breathalyzer cannot determine the difference between mouth alcohol and blood alcohol. Blood alcohol refers to the measurement of alcohol in the blood stream. If an individual has a blood alcohol measurement of .08% or above they can be arrested for DWI. Mouth alcohol, which can cause an individual’s blood alcohol levels to appear higher, is residual alcohol in the mouth. The residual alcohol can come from every day products like tooth paste and mouth wash as well as numerous medical conditions, as well as certain medications themselves. A criminal defense attorney will use a toxicologist as a witness to explain to a jury the effects residual alcohol can have on a breathalyzer test, in an effort to create reasonable doubt.
New York's legal BAC limit is .08, and while you may not be able to challenge this, you can challenge the fact your arrest was improper if it was based upon faulty lab or technical results. This includes the breathalyzer, urinalysis, or any blood tests administered that may have lead to inaccurate results, or that were mis-handled throughout the process
Alcohol takes a while to absorb into your system. While the alcohol is absorbing, your Blood Alcohol Content is still increasing. Legally, it does not matter what your BAC was when you were eventually tested at the police station, after having gone through a prolonged investigation. Legally, what does matter is your level of intoxication at the time you were operating your vehicle. A toxicology expert can be called as a witness and testify that the defendant’s BAC was lower than .08% at the time he/she was driving, and reached the higher, illegal limits after the motorist was operating his/her vehicle.
Affirmative defenses are a category of defenses that you can raise in defending your DWI, even if you have admitted to committing it. Some common examples of DWI affirmative defenses that may apply are “involuntary intoxication” (ie, someone spiked your drink or drugged you), “duress” (someone forced you into the vehicle and forced you to drive) and “emergency”.