Blood and Breath Tests in Mercer

When a police officer pulls you over on suspicion of DUI (Operating a Vehicle Impaired), they will almost certainly ask you to participate in one or more tests. This is standard operating procedure for law enforcement in Pennsylvania. The results of these evaluations form the primary evidence for most DUI charges. The tests are designed with a single purpose: to help the officer decide if drugs or alcohol have impaired your ability to operate a vehicle safely.

There are generally four specific types of testing methods used to gauge a driver’s level of sobriety:

• Field Sobriety Tests: Physical and visual tasks performed at the side of the road.
• Blood Tests: Chemical analysis of a blood sample.
• Urine Tests: Chemical analysis of a urine sample.
• Breath Tests: Analysis of breath alcohol concentration (often using a breathalyzer).

It is crucial to understand that these tests are not infallible. They can produce false positives, indicating a driver is intoxicated when they are actually sober. Conversely, they can sometimes fail to detect impairment. However, if a test result suggests you are drunk—even if you are not—you will likely still face arrest. To navigate these complex situations, you need a highly trained Mercer criminal lawyer who knows how to scrutinize the administration of these tests. An experienced attorney can examine the results, the behavior of the examiner, and the conditions under which the tests were taken to identify critical errors. These errors can be the key to getting charges lowered or completely dismissed.

Field Sobriety Tests

These evaluations are typically conducted at the roadside immediately after a traffic stop. Their primary goal is to demonstrate your physical coordination, balance, and ability to follow instructions simultaneously (divided attention). These responses help the police decide if there is probable cause for an arrest. The National Highway Safety Administration has standardized these three tests, and they are utilized in all fifty states.

The Walk and Turn Test

During the Walk and Turn Test, the driver is instructed to walk in a straight line, placing the heel of one foot against the toe of the other. You must take a specific number of steps while counting them out loud. The officer watches closely to see if you stumble, lose your balance, or start before the instructions are finished. If you lose count of your steps, step off the line, or use your arms for balance, the officer may document these as clues of impairment. A qualified Mercer DUI lawyer can often challenge the subjectivity of these observations in court.

The One Leg Stand Test

In the One Leg Stand Test, the instructions are to stand with your feet together and arms at your side. You are then told to raise one leg approximately six inches off the ground and balance on the other foot. While balancing, you must count out loud (often “one thousand one, one thousand two…”) until told to stop. This test typically lasts for 30 seconds. The officer is looking for four specific clues: swaying while balancing, using arms to balance, hopping to maintain balance, or putting the foot down.

The HGN (Horizontal Gaze Nystagmus) Test

The HGN test focuses entirely on the eyes. The police officer will ask you to follow a stimulus—such as a pen, finger, or flashlight—moving it from side to side. You must follow it with your eyes only, keeping your head still. The officer is looking for nystagmus, which is an involuntary jerking of the eyeball. This jerking becomes more pronounced when a person is under the influence of alcohol or certain drugs. Because this is a scientific test relying on precise administration, any deviation from protocol can be contested by a Mercer criminal lawyer.

Problems with Field Sobriety Tests

There are significant reliability issues with Field Sobriety Tests (FSTs). A major concern is the environment in which they are performed. They often take place on the side of the road, exposed to wind, rain, snow, or the glare of oncoming headlights. The physical condition of the road surface is also a major factor. The sides of Pennsylvania’s roads are often banked (sloped) to allow water to drain, and they may be narrow or pitted with potholes and gravel. These conditions make balancing difficult for anyone, regardless of sobriety.

Furthermore, personal physical attributes play a massive role. Medical conditions, weight, and age can all hinder the successful completion of these physical tasks. For instance, being overweight can make the physical mechanics of the Walk and Turn or One Leg Stand tests difficult to perform to the officer’s rigid standards. Senior citizens often suffer from natural balance degradation. Legal prescriptions, fatigue, or nervousness can also mimic signs of impairment. A Mercer DUI lawyer knows that failing these tests does not automatically prove intoxication.

Another critical point of failure is the training of the officer administering the test. If the officer was not adequately trained or failed to give instructions exactly as prescribed by the National Highway Safety Administration, their conclusions could be scientifically invalid. A Mercer criminal lawyer like Sean Logue, who has spent a decade defending clients against these charges, understands exactly what to look for. He reviews the dashcam footage and police reports to determine if the field sobriety tests were compromised by poor administration or environmental factors.

Blood, Breath, and Urine Tests

Beyond physical tests, police rely on chemical testing. Pennsylvania is an “implied consent” state. This means that by simply signing your name to receive a driver’s license and driving on Pennsylvania roads, you have already given your consent to submit to chemical DUI testing. If you are pulled over and arrested for DUI, you are legally required to submit to a blood, breath, or urine test if the officer requests it. While breath tests are sometimes done at the scene, official evidentiary tests are usually performed at a police station, state trooper barracks, or a hospital.

It is possible to refuse these tests, but there are immediate consequences. If you refuse, your license is automatically suspended by the Bureau of Motor Vehicles. This is an administrative penalty separate from the criminal charge. Understanding the nuance between the criminal case and the administrative suspension is a key area where a Mercer criminal lawyer can provide guidance.

Contact Us for Legal Assistance

Navigating the aftermath of a DUI stop can be overwhelming. The evidence against you—whether it’s a stumbled step on a roadside test or a chemical readout—can seem insurmountable, but it is often more fragile than it appears. If you have been asked to perform field sobriety or chemical testing to determine if you were intoxicated while driving, do not leave your future to chance.You need a defense team that understands the science and the law. Call the Mercer DUI lawyer team at 412.389.0805 at Logue Law Group immediately to discuss your case and begin building your defense.