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Sobriety Tests

The Law Office Phillips & Allen PA Nov. 20, 2022

When you are stopped by the police and the officer smells alcohol on your breath, you will likely be asked to step out of your vehicle. At this point, the officer begins observing your behavior for evidence to be used against you at your DUI trial. If you place your hand on the door to help yourself out of the vehicle or lean on the car at any point during the stop, the officer will note this as evidence of impairment in the arrest notes. If the officer suspects that you are driving under the influence of alcohol, you may be asked to submit to a field sobriety test, a chemical test, or both. These tests are primarily used as a means for the officer to collect evidence to support the charge against you. You have the right to refuse to submit to field sobriety and chemical tests. Refusing, however, may result in an automatic suspension of your driver’s license. In addition, it is important to remember that, because you are not yet officially under arrest, officers are not obliged to inform you of your right to refuse the tests before you take them.

Field Sobriety Tests 

Field sobriety tests, which are purportedly designed to detect a person’s mental and physical impairment, are often difficult to “pass” for those who are sober. Compound the difficulty of the tests with the fact they are usually performed at night with traffic whizzing by during a situation—a confrontation with the police—in which even the most composed person may be filled with anxiety, and it seems apparent that field sobriety tests are designed for you to fail. You have the right to refuse to take these tests by politely telling the officer that you’d prefer not to.

Three standardized field sobriety tests approved by the NHTSA are standing on one leg, walking heel to toe in a straight line, and moving your eyes from side to side while keeping your head facing forward, known as the horizontal gaze nystagmus test. The heel to toe test usually involves taking 9 steps, walking heel to toe in a straight line, turning, and taking 9 steps back. The one-leg-stand test requires you to balance on one leg with your hands down at your sides while counting to 30. Both of these tests can be difficult for some people to perform under the most favorable conditions, especially if they are overweight or have a back, knee, or ankle injury, an inner ear infection, or other illness which affects the human body’s ability to balance. The horizontal gaze nystagmus test involves moving your eyes from side to side while following an object that the officer is moving, while keeping your head facing forward. The test is intended to detect involuntary jerking eye movements that indicate drug or alcohol impairment. However, these jerking eye movements can be produced by other factors, such as illness or injury. Police may use other non-standardized tests, as well, including reciting a portion of the alphabet, counting backwards, or standing with your feet together while tipping your head backwards.

Field sobriety tests are overwhelmingly subjective and inaccurate and often primarily serve to arm police with evidence that can be used against you at your DUI or DWI trial. It isn’t often that police decide not to arrest a person based solely on the results of field sobriety tests.

Chemical Tests 

Chemical tests measure the amount of alcohol in your body by assessing the blood alcohol concentration (BAC) in your bloodstream. BAC is measured as the percentage of alcohol in your blood as demonstrated by a breath, blood, or urine test. The chemical test that is most widely used in Maryland is the breath test. A breath test measures the alcohol that is contained deep in your lungs. The percentage of alcohol in your lungs is proportional to the percentage of alcohol in your blood.

In Maryland, a driver with a BAC of .08% or higher is considered “per se intoxicated.” Therefore, if a breath, blood, or urine test proves that you are at or over this blood concentration level, no further proof of impairment is necessary to charge you with DUI. If the chemical test shows that you have a BAC of .07% to .08%, it is considered prima facie evidence of driving while impaired (DWI). If the chemical test shows that you have a BAC of .05% to .07%, it is considered neutral—that is, it neither proves nor disproves that you are under the influence of or impaired by alcohol. A test result of less than .05% BAC carries with it a presumption that you are not under the influence or impaired by alcohol. Persons under the age of 21 are subject to “zero tolerance BAC,” which makes it illegal for a driver under the legal drinking age to have even a small blood alcohol concentration. If you are under the age of 21 and have a BAC of .02% or higher, no further proof of impairment is necessary to charge you with DUI or DWI. The following table outlines the presumption of guilt associated with various BAC levels.

BAC Level


.08% or higher

Per se guilt of DUI

.07% up to .08%

Prima facie guilt of DWI

.05% up to .07%

Neutral—proves neither guilt nor innocence of DUI or DWI

Less than .05%

Per se innocence of DUI or DWI

Higher than .02%

Per se guilt of DUI for persons under 21

If you are arrested for DUI or DWI, you have the right to speak with an attorney before submitting to a breath test. If the police deny you the right to counsel, it may help to attack the prosecutor’s case against you, both at your administrative hearing and at your criminal trial.

Even if your breath test shows that you had a BAC over the legal limit, there are defenses that can be used to challenge the accuracy of the test. For example, the accuracy of breath tests can fluctuate depending on factors like body temperature and cellular composition of blood. Breath tests are designed to work accurately at a normal body temperature of 98.6 degrees Fahrenheit. If you can provide evidence of a higher body temperature due to a cold or the flu, for example, the accuracy of the breath test may be challenged. In addition, breath tests assume an average red and white cell volume of blood of 47%. However, if you can present evidence that the cell volume of your blood is different, it can compromise the accuracy of the breath test. In some cases, defendants have been able to prove that the machine used to conduct the breath test was malfunctioning or that the test was improperly administered. In addition, if you use an asthma inhaler or are diabetic, the machine may have rendered a false reading.

Police officers often request that you submit to a preliminary breath test (PBT) during your traffic stop in order to determine whether or not to arrest you for DUI or DWI. This is not an official breath test. You have the right to refuse this test without any penalty, and the results of this test may not be used against you in court. However, you may use the favorable results of a PBT as a defense to your DUI or DWI charge. Before administering a PBT, the officer is required to inform you of your rights regarding this test. Officers often fail to properly advise citizens of their rights before giving the PBT and do not always disclose the results of the preliminary test to the accused.

Implied Consent 

Maryland’s implied consent laws mandate that a driver suspected of driving under the influence of alcohol must submit to a chemical test or incur a penalty of mandatory suspension of his or her driver’s license for up to 1 year. The theory of implied consent arises from the notion that driving is a privilege, not a legal right. Thus, by virtue of possessing a driver’s license, you have impliedly consented to having your BAC tested. If you refuse to submit to a breath or blood test, your license may be immediately suspended for up to 1 year. If you are involved in a crash and are unconscious (or even dead) as a result, you are not considered to have waived this implied consent. In addition, your refusal to take a chemical test may be used against you as evidence of your consciousness of guilt in court.

For more information on Sobriety Tests In Maryland, a free initial consultation is your next best step. Get the information and legal answers you are seeking talk Arnold F. Phillips by calling today.