If you’ve been pulled over on suspicion of drunk driving in California or are researching DUI laws to understand your rights, you’ve likely come across the terms PAS test and chemical test. These two types of tests are often confused, but they serve different purposes and carry different legal implications. Knowing the distinction can make a significant difference in how you respond during a DUI stop and the consequences you might face.
This guide will explain what each test is, how they are used, your rights, and what can happen if you refuse either test.
What Is a PAS Test in California DUI?
PAS stands for Preliminary Alcohol Screening. It is a portable breathalyzer used by law enforcement officers during a DUI stop to estimate a driver’s blood alcohol concentration (BAC) before an arrest is made.
The PAS test is administered on the roadside, typically after an officer observes signs of impairment and may also have asked you to perform field sobriety tests. Its primary purpose is to provide officers with preliminary information to determine whether there is probable cause to arrest a driver for DUI.
In California, PAS tests are generally voluntary for most drivers over 21 who are not on DUI probation. Refusing the PAS test in these cases usually does not result in penalties. However, there are exceptions for drivers under 21, due to zero-tolerance laws, and drivers on DUI probation. In these situations, refusing a PAS test can lead to immediate administrative consequences, including license suspension.
What Is a Chemical Test in a California DUI?
A chemical test refers to official BAC testing conducted after a DUI arrest. Unlike the PAS test, this test is required under California’s implied consent law. Once a driver is lawfully arrested for DUI, submitting to a chemical test is legally expected.
Chemical testing can include breath tests using state-approved devices, blood tests, or urine tests, especially if drugs are suspected or other tests are unavailable. These tests provide a scientifically reliable measure of a driver’s BAC or the presence of drugs in the system and are commonly used as evidence in DUI prosecutions.
California’s implied consent law means that by driving in the state, you are considered to have agreed to chemical testing if lawfully arrested for DUI. Refusing a chemical test after arrest triggers automatic administrative penalties, regardless of the outcome of the DUI case itself.
Key Differences Between PAS and Chemical Tests
The main distinction between the PAS and chemical tests is timing and legal effect. PAS tests help officers decide whether to arrest, while chemical tests are used to prosecute DUI and have significant legal consequences if refused.
PAS tests are conducted roadside before an arrest and are generally voluntary. Refusing usually has no legal penalty unless you are under 21 or on DUI probation. Chemical tests are administered after a lawful arrest, are required under implied consent, and refusal carries statutory penalties such as license suspension, fines, and increased consequences in court.
PAS test results are preliminary and often not admissible in court, while chemical test results are scientifically reliable and are used as strong evidence to prove intoxication.
Refusing a PAS Test
For drivers over 21 who are not on DUI probation, refusing a PAS test usually has no legal penalty. Officers may still proceed with other sobriety tests or arrest based on observed impairment, but refusal alone does not trigger statutory consequences.
For drivers under 21 or on DUI probation, refusing a PAS test can result in administrative penalties, including license suspension. In these cases, refusal is taken more seriously because underage and probationary drivers are subject to stricter alcohol testing rules.
Refusing a Chemical Test
Refusing a post-arrest chemical test has significant consequences. A first refusal can result in a one-year driver’s license suspension. Subsequent refusals or prior DUI/refusal within 10 years increase the suspension period. Refusal can also impact your criminal case, as it may be used as evidence against you and lead to more severe penalties if convicted of DUI. Additional consequences may include mandatory DUI school or extended probation periods.
While you technically can refuse, it is almost always disadvantageous. The implied consent law ensures that refusal carries automatic penalties, and in most cases, taking the chemical test may lead to a less severe outcome than outright refusal. The decision to refuse should only be made with careful legal advice from an experienced DUI attorney, as the consequences can be severe and long-lasting.
It is important to note that refusing a PAS test does not protect you from chemical test penalties. Once arrested, the implied consent law applies, and refusal carries statutory consequences.
How Test Results Are Used in Court
PAS test results are preliminary and often not admissible in court as evidence for conviction. They serve primarily as an investigative tool for the officer rather than definitive proof of intoxication.
Chemical test results, however, are scientifically reliable and typically used as strong evidence in DUI prosecutions. Breath, blood, or urine test results showing a BAC over the legal limit (.08% for adults) are central to most DUI cases in California.
Practical Tips if You’re Pulled Over
Remain calm and courteous, and comply with officer instructions for safety. Know your rights regarding PAS tests — for most adult drivers not on probation, PAS testing is voluntary. Understand that after a lawful arrest, chemical testing is required under implied consent laws. Request legal counsel immediately if arrested, and attend your DMV hearing if refusal or high BAC testing triggers license action.
Knowing the difference between PAS and chemical tests, and your rights regarding each, can help you navigate a DUI stop and avoid unnecessary penalties.
Summary: PAS Test vs. Chemical Test
PAS Test: Conducted roadside before arrest, usually voluntary, minimal or no statutory consequences if refused, primarily a tool for officers to determine probable cause.
Chemical Test: Administered after arrest, required under implied consent, refusal triggers automatic license suspension and additional penalties, results are admissible in court as strong evidence.
Understanding these distinctions ensures you are better prepared for a DUI stop and know what to expect at each stage of the process.
Protect Your Rights with Southwest Legal
If you or a loved one is facing a DUI in Southern California and have questions about PAS or chemical testing, Southwest Legal can provide experienced legal guidance. Protect your rights, understand your options, and get the professional support you need to navigate California DUI laws effectively. Contact us today for a free consultation.
