The Role of the Preliminary Alcohol Screening (PAS) Test in California DUI Cases

The Preliminary Alcohol Screening (PAS) test plays a crucial role in California DUI cases. This test, typically administered at the scene of a traffic stop, helps law enforcement officers determine whether a driver is under the influence of alcohol. Understanding the function, reliability, and implications of the PAS test is essential for anyone involved in a DUI case in California.

The PAS test is a breathalyzer test conducted using a handheld device during a DUI stop. It measures the blood alcohol concentration (BAC) in a driver’s breath. The PAS test is different from the Evidentiary Breath Test (EBT) conducted at the police station, which provides a more precise measurement of BAC and is used as primary evidence in court.

Under California Vehicle Code Section 23152, it is illegal to drive with a BAC of 0.08% or higher. For drivers under 21, the limit is 0.01%, and for commercial drivers, it is 0.04%. The PAS test is a tool used by officers to establish probable cause for a DUI arrest and to determine whether further testing is warranted.

The PAS test is usually administered after the officer observes signs of impairment, such as erratic driving, slurred speech, or the smell of alcohol. It is part of the field sobriety testing process, which may also include physical tests like the walk-and-turn or one-leg stand.

In California, drivers who are 21 or older and not on DUI probation have the right to refuse the PAS test without facing immediate penalties. However, refusal can lead to complications, as it may be used against the driver in court. For drivers under 21 or those on DUI probation, refusal to take the PAS test can result in an automatic one-year license suspension under California's implied consent law.

While the PAS test is a useful tool for officers, its accuracy and reliability can be subject to challenge. Several factors can influence the test results:

The accuracy of a PAS device depends on regular calibration and maintenance. If the device is not properly maintained, it can produce inaccurate readings. Defense attorneys often request maintenance records to challenge the reliability of the PAS test results.

Various external factors can affect PAS test results. For instance, residual mouth alcohol from recent drinking, mouthwash, or certain medications can lead to falsely high BAC readings. Environmental conditions, such as temperature and humidity, can also impact the device’s accuracy.

The timing of the PAS test in relation to the last drink can influence the results. Alcohol absorption rates vary, and a test taken shortly after drinking may not accurately reflect the driver’s BAC at the time of driving. Conversely, a test taken later may show a higher BAC as the alcohol is fully absorbed into the bloodstream.

The PAS test is an important piece of evidence in DUI cases, but it is not infallible. Skilled defense attorneys can challenge the test’s validity and use various strategies to undermine its reliability.

One strategy is to question the legality of the initial traffic stop. Officers must have reasonable suspicion to pull over a driver. If it can be shown that the stop was unjustified, any subsequent evidence, including the PAS test results, may be deemed inadmissible.

The proper administration of the PAS test is critical. Defense attorneys will scrutinize whether the officer followed the correct procedures when conducting the test. Any deviation from the protocol can be grounds to challenge the results.

Attorneys can present alternative explanations for the PAS test results, such as medical conditions, dietary factors, or improper use of the device. Expert witnesses may be called to testify about the potential for false positives or inaccurate readings.

It is important to highlight that the PAS test is preliminary and not as accurate as the Evidentiary Breath Test. The defense can argue that the PAS results should not be given significant weight compared to more reliable testing conducted later.

The Preliminary Alcohol Screening (PAS) test is a critical tool used in California DUI cases to establish probable cause for arrests and to determine impairment. While it provides law enforcement with an immediate assessment of a driver’s BAC, its results are not always definitive. Various factors can influence the accuracy of the PAS test, and it is often subject to challenge in court.

For those facing DUI charges, understanding the role and limitations of the PAS test is crucial. A knowledgeable DUI defense attorney can effectively challenge the validity of the PAS test results and explore all possible defenses to achieve the best outcome in a DUI case. By scrutinizing the procedures and evidence, the defense can help ensure that the rights of the accused are protected and that justice is fairly administered.