When You’re Facing Tough Times…
Real Help That Makes A Difference

Preliminary / Portable Breath Test (PBT)

Preliminary breath testing is another stage of the pre-arrest screening phase of DUI detection.

The Washington Administrative Code provides that preliminary breath testing is voluntary. WAC 448-15-020. Individuals also have a common law right to decline field sobriety tests. City of Seattle v. Stalsbroten, 138 Wash. 2d 227, 237, (1999). However, the Washington Supreme Court has held that admitting evidence of a defendant’s refusal to perform a field sobriety test does not offend the Fifth Amendment right against incrimination and that it is constitutionally permissible to admit evidence of a defendant’s refusal to take a field sobriety test. Stalsbroten, 138 Wash. 2d at 237-239.

But breath testing is different than other standard field sobriety tests (SFSTs).  Breath testing constitutes a search for Fourth Amendment purposes. Skinner v. Railway Labor Executives’ Ass’n, 489 U.S. 602, 616-617 (1989) (explaining urine, blood, and breath testing are searches). And it is generally improper to use a Defendant’s invocation of his constitutional right to refuse consent to a warrantless search as substantive evidence of his guilt. State v. Gauthier, 174 Wash.App. 257 (Wash. Ct. App. 2013). Therefore, a refusal to submit to a PBT test should not be admissible as evidence of guilt. See City of Vancouver v. Kaufman, 10 Wash.App.2d 747 (Wash. Ct. App. 2019) (trial court erred in allowing state to present evidence that driver’s refusal to submit to PBT test showed consciousness of guilt). Therefore, drivers should consider politely refusing a PBT as there should be no adverse consequences for doing so. Drivers do not need to prove their innocence. The prosecution must prove guilt beyond a reasonable doubt. In general, less evidence is more from a criminal defense point of view.

Is The Roadside Breathalyzer (PBT) Admissible?

A PBT is inadmissible for any purpose in the absence of a Frye hearing or specific approval of the device and its administration by the state toxicologist. State v. Smith, 130 Wash.2d 215, 222 (1996). PBT devices have been approved only for establishing probable cause. WAC 448-15-010. PBT results should not be used for determining whether a person’s breath alcohol concentration exceeds .08 or more under the DUI statute. WAC 448-15-010. Therefore, even if a driver submits to a PBT, the result should not be admissible at trial.  The administration of such a test and surrounding circumstances are arguably irrelevant as well in light of these principles.

A PBT result may also be attacked for purposes of challenging probable cause. Residual mouth alcohol that remains in mouth tissue can impact the accuracy of the test and may cause the PBT result to be higher than the test subject’s true breath or blood alcohol concentration. Other breath contaminants such as ether, acetone, acetaldehyde, cigarette smoke, and other contaminates may result in a false or inaccurate reading. A specific test protocol must also be followed by the officer utilizing the PBT device. WAC 448-15-030. Failure to follow the protocol may negate the accuracy of the test for purposes of probable cause. The PBT device must also be certified every sixth months. A protocol approved by the state toxicologist must be followed in order for a PBT device to be certified. WAC 448-15-040. The officer operating the PBT device must also be certified to use the instrument. WAC 448-15-050.

Contact the DUI defense attorneys at Platt, Thompson and Buescher today to talk about resolving your DUI charge. Our DUI attorneys serve Oak Harbor, Island County, Bellingham, Burlington, Mt. Vernon, Whatcom County, Skagit County, Seattle, King County, and greater western Washington. Call our Coupeville office to schedule an appointment by at 360-474-3994 or contact us online.