It’s a motion under Penal Code section 1538.5 to suppress evidence obtained from an illegal search under the Fourth Amendment.
In a DUI situation, the challenge can be to either the initial stop (arguing that the officer did not have reasonable suspicion of criminal activity in order to lawfully detain you) or the arrest (claiming that there was not probable cause to arrest you).
If we are successful on either grounds, then any resulting evidence, including any chemical test, will be suppressed.
If we prove the initial stop is bad, then any observations of you – the smell of alcohol, your physical symptoms, etc – and the chemical test will be out. There’s no way the DA can go forward and your case will be dismissed.
If the initial stop is ruled valid, but the arrest or taking of evidence was somehow improper, then any subsequent evidence (such as statements, chemical tests, etc) will be excluded. If the DA thinks they have enough to go forward without the evidence that was suppressed, you can still face a trial, but that depends on all the facts of your case.
If you have questions about the validity of your traffic stop for DUI (or any other case where a traffic stop led to criminal charges), let’s schedule a time to discuss the facts in detail.