Chicago Criminal Lawyer Blog
In Illinois, being charged with a DUI (Driving Under the Influence) can carry serious legal consequences, including potential jail time, fines, and the suspension of driving privileges. Often, one of the most critical pieces of evidence in a DUI case is the driver’s Blood Alcohol Concentration (BAC) obtained from a chemical test. However, BAC chemical tests are not infallible, and there are several ways to challenge their accuracy in Illinois. Understanding how to contest these test results can be crucial to mounting a successful defense.
Understanding BAC Chemical Tests in Illinois
In Illinois, law enforcement officers use three primary types of chemical tests to measure a driver’s BAC:
- Breath tests: Commonly conducted roadside or at the police station using breathalyzer devices.
- Blood tests: Conducted by qualified medical professionals to measure alcohol or drug levels in the bloodstream.
- Urine tests: Generally used when drug impairment is suspected, though less frequently than breath or blood tests.
Each test aims to establish whether the driver’s BAC exceeds Illinois’ legal limit of 0.08% for most drivers, 0.04% for commercial drivers, and 0.00% for drivers under the age of 21. However, despite their perceived accuracy, these tests can be susceptible to errors due to various factors, making them open to challenge.
Legal Grounds for Challenging BAC Chemical Test Results
When building a defense against BAC results in a DUI case, several legal grounds can be considered. Below are some of the primary defenses that can help dispute the accuracy or admissibility of BAC test results:
1. Improper Testing Procedures
The accuracy of a BAC chemical test depends heavily on whether the test was administered correctly. In Illinois, police officers are required to follow strict protocols when administering breath, blood, or urine tests. For instance, breathalyzer tests should be conducted by certified operators, and the equipment must be in proper working order. If the officer failed to follow correct procedures, such as not observing the driver for at least 15 minutes before administering the test, the results could be invalid.
In addition, blood samples must be drawn by a qualified medical professional and follow a specific chain of custody to avoid contamination. Any deviation from these protocols can introduce doubt as to the validity of the results.
2. Calibration and Maintenance Issues with Breathalyzers
Breathalyzer machines require regular calibration and maintenance to ensure accurate readings. If the machine has not been properly calibrated, it may produce incorrect BAC readings, resulting in false positives or inflated BAC levels. Illinois law mandates regular calibration and maintenance records for breathalyzer devices, and these records are admissible in court.
If an attorney can show that the breathalyzer device used in the arrest had calibration or maintenance issues, the court may rule the BAC evidence as unreliable, which can weaken the prosecution’s case.
3. Physiological Factors Affecting BAC Results
Certain physiological factors can impact BAC test results, leading to inaccuracies. Medical conditions such as acid reflux, diabetes, or hypoglycemia can sometimes cause elevated BAC readings on breathalyzer tests. For instance, individuals with acid reflux or gastroesophageal reflux disease (GERD) may have alcohol from their stomach brought into their mouth, resulting in a falsely elevated breathalyzer reading.
Similarly, certain medications and diets (such as those following a ketogenic diet) can cause the body to produce isopropyl alcohol, which may register on a breathalyzer. If an individual has a legitimate medical condition that could affect their BAC test, an attorney can introduce this as a factor to challenge the results.
4. Mouth Alcohol Contamination
Breathalyzer tests are designed to measure deep lung air rather than alcohol present in the mouth. However, recent consumption of alcohol, use of mouthwash, cough syrups, or other substances can leave residual alcohol in the mouth, which could falsely elevate BAC results.
The 15-minute observation period prior to a breathalyzer test is intended to allow any mouth alcohol to dissipate, but if this period was not followed strictly, it opens up a significant area for challenge.
5. Rising Blood Alcohol Defense
The rising blood alcohol defense is based on the fact that alcohol takes time to absorb into the bloodstream. BAC levels may continue to rise after an individual has stopped drinking, meaning that their BAC could be higher at the time of testing than it was while driving.
For instance, if a driver consumed alcohol shortly before getting behind the wheel, their BAC could be below the legal limit while driving but above the limit by the time the test is administered. This defense requires a detailed analysis of the timing of alcohol consumption, the traffic stop, and the BAC test.
6. Chain of Custody Errors
In cases where blood or urine samples are used to determine BAC, proper chain of custody is critical. The chain of custody refers to the documented handling of evidence from the time it is collected to when it is analyzed in the lab. Any break in this chain or mishandling of the sample could lead to contamination or tampering, making the test results unreliable.
If there is evidence that the sample was improperly handled or stored, or if there are gaps in the documentation, this may lead to the exclusion of the test results from evidence.
7. Unqualified Personnel Administering the Test
Illinois law requires that only certified personnel administer and process BAC tests. For breathalyzer tests, this means the officer must have specific training and certification. For blood tests, only medical professionals are authorized to draw blood for BAC testing.
If an unqualified person administered the test or handled the sample, the results could be deemed invalid in court, as they may not meet the necessary standards for admissible evidence.
Why Challenging BAC Test Results Matters in Illinois DUI Cases
The prosecution in an Illinois DUI case relies heavily on BAC test results to prove impairment. Successfully challenging these results can significantly weaken the prosecution’s case and increase the chances of a favorable outcome, whether through reduced charges, dismissal, or acquittal. Without BAC evidence, proving that the driver was legally intoxicated becomes more challenging for the state.
An experienced DUI defense attorney is essential for effectively challenging BAC results. Attorneys with a comprehensive understanding of Illinois DUI laws and scientific knowledge of BAC testing can identify potential weaknesses in the evidence and question the prosecution’s claims.
Additional Evidence to Support a Defense Against BAC Test Results
Aside from challenging BAC test results, defense attorneys may also present additional evidence to support the driver’s innocence. This could include:
- Witness Testimony: Friends, family, or bystanders who observed the defendant’s behavior before the arrest may testify that they did not appear intoxicated.
- Video Footage: Many police vehicles are equipped with dashcams, and officers may also use bodycams. These recordings can be useful in demonstrating the driver’s behavior and questioning whether they showed signs of impairment.
- Medical Records: Medical records confirming conditions that can influence BAC levels may also serve as critical evidence in a defense strategy.
The Importance of a DUI Defense Attorney in Challenging BAC Test Results
Defending against a DUI charge in Illinois requires a detailed understanding of both state laws and the scientific principles behind BAC testing. A skilled DUI attorney will carefully examine every aspect of the testing process to identify inaccuracies, errors, or procedural missteps that could benefit the defense.
At The Law Offices of David L. Freidberg, we specialize in challenging BAC test results in Illinois DUI cases. With decades of experience in DUI defense, our firm is dedicated to providing clients with a comprehensive and personalized defense strategy. We scrutinize every detail, from the arrest process to the test results, to build the strongest possible case for your defense.
Call Us For Your Free Consultation
If you are facing DUI charges in Illinois, challenging BAC test results could make a significant difference in your case outcome. Contact The Law Offices of David L. Freidberg for skilled legal assistance. With decades of experience and a commitment to protecting your rights, we offer a free consultation 24/7 at (312) 560-7100 or toll-free at (800) 803-1442. We serve clients throughout Chicago, Cook County, DuPage County, Will County, and Lake County in Illinois. Let us help you navigate the legal system and fight for your future.
