PAS Versus Breath Test in Plain Terms
Drivers often blow into two different devices in one night and assume they are the same test. They are not. The PAS versus breath test difference turns on timing and purpose. The roadside device helps the officer decide whether to arrest, while the later breath test is the chemical test under implied consent.
Vehicle Code section 23612 calls the preliminary alcohol screening test a field sobriety test. It is an investigative tool that comes before arrest.
The Roadside Screening Test
Before an arrest, the officer may ask for a PAS sample. The officer must tell the person the PAS is to help decide whether the person is under the influence. The officer must also say the person may refuse it.
That right to refuse has limits. Drivers under 21 and drivers on DUI probation who are lawfully detained are deemed to consent to screening under Vehicle Code sections 23136 and 23154.
The Evidential Breath Test
After a lawful arrest, implied consent applies to a chemical test of blood or breath. Section 23612 also says the PAS does not satisfy that duty. So a person who took the roadside test still has to take the chemical test.
Evidential breath testing follows state rules. Under Title 17 section 1221.2, each test includes two separate samples that do not differ by more than 0.02 grams per 210 liters of breath.
PAS Versus Breath Test for Refusals
Refusing the roadside PAS is generally different from refusing the chemical test after arrest. The chemical test refusal carries DMV suspension or revocation periods. The article on California DUI test refusal explains those consequences.
For drivers under 21 or on probation, refusing the PAS can itself lead to DMV action. That is why the PAS versus breath test question depends on who the driver is.
No Breath Sample Is Kept
A breath test does not keep a sample for later analysis. Vehicle Code section 23614 says the person must be told this and offered a blood or urine sample to retain at no cost. The guide on DUI blood retest requests covers what can happen with that sample.
What to Note
Write down which device came first, where each test happened and what the officer said before each one. Even small details, such as whether the officer watched the person before the test, can help.
Records from the breath instrument also exist. The article on breathalyzer calibration records explains how lawyers review them. Those details help a lawyer compare the report with the PAS versus breath test rules.
The article on personal breathalyzer accuracy explains how consumer devices compare with evidential instruments.