Challenging the Results of Chemical Tests in a DUI Case
Chemical tests, also known as sobriety tests, are conducted to determine whether a driver is operating a motor vehicle while under the influence of alcohol or other controlled substances. By testing for the presence of controlled substances, law enforcement can determine whether a driver is intoxicated.
As in any criminal case, the prosecution has the burden of proving a defendant guilty beyond a reasonable doubt. This means that a defendant does not need to prove anything, but only must show that the evidence is insufficient or that the arrest was improper in order to obtain a Not Guilty verdict.
Types of Chemical Tests
Law enforcement uses three kinds of test to determine whether a driver is under the influence of alcohol of other controlled substances. These tests might include a blood, breath, urine, or saliva test. Regardless of the type of test administered, a skilled criminal defense attorney can challenge the results of the test. If successful, the prosecution is much more likely to agree to a favorable plea bargain, or even dismiss the case.
The breath test is the most common form of chemical test used to evaluate a driver’s blood alcohol level. However, a breath test cannot be used to test for other controlled substances, such as marijuana. A breath and saliva tests for marijuana are in development but are not currently being used by law enforcement.
Many breath tests can be administered at the roadside, which makes them a convenient option to provide a preliminary assessment of whether a driver is under the influence of alcohol. If a roadside test comes back positive for the presence of alcohol, the driver will be arrested and taken to the police station for a more sophisticated test that measures the driver’s actual alcohol concentration.
Many factors influence the accuracy of a breath test including temperature, atmospheric pressure, the chemical composition of the alleged offender’s blood, the driver’s level of physical activity, hyperventilation, certain medical conditions, and what the driver had to eat prior to the test.
The breath test needs to be properly calibrated. If it is not, the results of the test are not reliable and evidence of the test results should be excluded. To use the results of a breath test as evidence, the prosecutor must provide testimony from the officer who administered the test that the machine was properly calibrated at the time of the driver’s test.
Your lawyer can also challenge whether the police officer who administered the breath test was properly trained. If the officer administering the test lacked the proper training, the results of the test may be excluded.
Blood and Urine Tests
Police can also test your blood alcohol content using a blood draw or a urine test.
Blood and urine tests are generally more accurate than breath tests, and also test for other controlled substances. If the police officer believed you were under the influence of a controlled substance that is not alcohol, you were probably asked to submit to a blood test or a urine test to determine whether controlled substances are present in your system, and to make a determination whether you are under the influence.
However, blood and urine tests can also be unreliable, and therefore potentially inadmissible, if:
- The blood sample was contaminated by the alcohol swab used before drawing the blood
- The blood sample was not drawn by someone qualified to administer the test
- The sample was taken too long after the initial arrest
- The sample was improperly stored or transported
- The sample is not from the driver accused of being under the influence (chain of custody problems)
Blood tests are typically not administered at the scene because they require a qualified person, such as a nurse or phlebotomist, to administer the test. Similarly, urine tests are not typically administered on scene.
If the blood test was not administered by a qualified person, your lawyer can challenge the results of the blood test on that basis.
In 2016 the US Supreme Court decided that police need to obtain a warrant to compel a driver to submit to a blood test if the driver refuses. The North Dakota Supreme Court later applied the same requirements to urine testing. A warrant is not required for a breath test, and a person can be criminally charged for refusing a breath test.
Challenging the Results of an Alcohol Content Test
Your lawyer can challenge the accuracy of the equipment used to test your blood, urine, or breath, or the testimony of the arresting officer that was used as probable cause to administer the test in the first place.
If the court finds that the reason for the test was improper, or that the test was improperly administered, the results of the test may be thrown out and cannot be considered as evidence of a driver’s intoxication. In this case, the prosecution is left with the officer’s testimony that the driver was intoxicated. This evidence is generally less persuasive than the results of a chemical test and can often lead to the case being dismissed, or negotiation of a favorable plea bargain.
Chemical tests can be inaccurate. The Intoxilyzer 8000 has a variance of +/- .005, which means that a .08% might be as low as .075% or as high as .085%.
Even if the judge does not exclude the alcohol test evidence, your lawyer can still argue to the jury at trial about the scientific reliability of the evidence.
Other Ways to Challenge BAC Test Results
In addition to challenging the results of the test itself, your lawyer may be able to challenge whether the officer had probable cause to administer the test in the first place. If the police officer is not present to testify at trial, your lawyer may be able to have evidence of the test results excluded.
Lack of Probable Cause
If the police officer lacked probable cause to believe a driver was under the influence, the results of the chemical test might be excluded because the search was illegal.
In order to establish probable cause, the arresting officer must show that he had:
- Reasonable suspicion to pull you over. This is usually testimony that you were driving erratically or breaking some other traffic law.
- Probable cause to believe that the driver was intoxicated. This is usually testimony that the driver had slurred speech or glassy eyes, or that the officer detected an “odor of alcohol emanating from the vehicle.”
Sixth Amendment Right to Confront Your Accuser
A defendant has the right to confront his accuser. If the arresting officer or the officer who administered the test is not present in court at trial, the defendant is deprived of his Sixth Amendment right to confront his accuser. Likewise, if the lab technician or the person analyzing the blood, urine, or saliva sample is not present, there might be a Sixth Amendment confrontation clause violation. In either of these situations, the defendant can seek to have the results of the test excluded on that basis.
Implied Consent / Refusal
A driver is not required to submit to a chemical test; however, there are penalties for refusal. When a driver applies for a driver’s license, he consents to be stopped on public roadways on suspicion of drunk driving and consents to any tests to determine if the driver is impaired. Refusing a chemical test violates the implied consent arrangement and subjects the driver to a license suspension or revocation for refusing a lawfully requested breath chemical test. The driver may also be charged with a crime.
A Criminal Defense Lawyer Can Challenge the Results of a BAC Test
Many people wrongly believe that if they test above the legal limit they will automatically be convicted of driving under the influence.
A criminal defense lawyer can challenge the results of a chemical test on general scientific grounds, and on the way the test was administered in your particular case. These challenges can result in the test result evidence being excluded, or to raise reasonable doubt about a defendant’s guilt.
Fremstad Law Moves Your Forward from a DUI Charge
If you or someone you care about is facing DUI charges in North Dakota, the experienced criminal defense lawyers at Fremstad Law are here to help.
Contact Nick Thornton today by calling (701) 639-2326.