“Blood or Breath?”

By Thomas Daly

This all-too-classic question that a police officer asks anyone who has just been arrested for driving under the influence is both frightening and full of many possible constitutional violations. The emotion is real, the potential analysis long and complex, and the legal ramifications both complicated and serious. But, of course, all anyone wants to know is: what is best, should they do a blood or a breath test? This author has heard it from so many friends, both lawyers and non-lawyers; they want help or guidance should they ever be in the terrifying situation of being under investigation for driving under the influence.

To that question, this author can only laugh and give the most classic ”lawyer answer” of all time: it depends.

The way in which DUI defense works can change dramatically if a person refuses a test, does a breath test, does a blood test, or in some instances chooses to do both (generally, it is not an ideal situation to do both.)

There are defenses that are unique to one testing device versus the other. Calibration and maintenance logs in a breath testing case can be helpful if they show the breathalyzer device was not working properly. Blood testing usually sets up a greater amount of time between the time of driving and time of testing, and errors may occur in the testing process. Obviously, there are many, many more issues that are relevant to either or both tests. For the purposes of this discussion, please note that testing via the Preliminary Alcohol Screening (PAS) device may be refused, as it is not a breathalyzer.

One main difference that has been a subject of intense litigation for the past several years is the varying Fourth Amendment implications of each test. The Fourth Amendment of the United States Constitution prohibits unreasonable searches, and the taking of a blood sample or the administration of a breath test is undoubtedly a “search.”

For decades, the state of the law in obtaining toxicology evidence was seemingly simple. The landmark case of Schmerber v. California (1966) 384 U.S. 757, essentially held that if a person refuses to consent to a test, the officer can forcibly obtain a blood sample. The basis for this was that there was no time or ability to obtain a warrant and the dissipation of alcohol in the human body constituted an exigent circumstance.

This finally started to change nearly 50 years later in McNeely v. Missouri (2013) 569 U.S. 141.

The McNeely court recognized that, while an exigency could still justify a warrantless blood draw, technology has changed and the ability to quickly obtain a warrant is now possible. McNeely did not do away with exigency as a basis for a blood draw, but it did make it much more difficult for the police and prosecution to justify a blood draw under exigency. Most local police departments have a standard two-page warrant application for a blood draw which can be electronically submitted to an on-call judge. If the police have time to get the warrant, then they should do that. To argue that the blood was taken under exigent circumstances likely requires some unique reason as to why law enforcement could not obtain a warrant.

A few years later, the Supreme Court decided Birchfield v. North Dakota (2016) 579 U.S. 438. In Birchfield, the court considered three DUI cases together. They concluded that blood tests are different than breath tests and that the former involves a greater intrusion, and therefore is afforded greater protection under the Fourth Amendment. Simply put, the court held that the Fourth Amendment permits warrantless breath tests, but not blood tests, incident to arrest for drunk driving.

Cases have continued to roll in, trying to analyze when a blood test can be lawfully taken. A valid warrant justifies the test, but outside of a warrant, there must be a valid exception to the warrant requirement. The most common exception relied upon is consent.

But this then begs the question, what is “valid consent’?” Remember the case, Bumper v. North Carolina (1967) 391 U.S. 543, from law school? The court discussed that there is a difference between consent that is freely and voluntarily given and acquiescence to a claim of lawful authority.

The police consistently rely on the supposed requirement to submit to a chemical test (“implied consent”) which is codified at Vehicle Code section 23612. This is the code section that mandates DMV administrative penalties for DUI and states that refusal to submit to a chemical test can result in a longer driver’s license suspension. The police “admonish” a DUI suspect of the “obligation” to submit to a test. Some officers are better than others at actually explaining the distinction. Some do a good job of explaining that refusal of the test is an option but will result in more significant consequences; some explain it poorly or not at all. This author has had cases where officers simply state that the driver is required to submit to a chemical test, and the driver responds only by saying “okay.”

Is that valid consent? Is it free and voluntary? Or is it acquiescence to a claim of lawful authority?

For a criminal defense attorney, it is certainly an opening to file a motion to suppress evidence for a Fourth Amendment violation.

So, what’s best? Blood? Breath? Refuse to give consent?

There is probably no right or wrong answer. Each case is so unique that different strategies will evolve regardless of what test was, or was not, done. However, knowing that the defenses and Fourth Amendment implications are different for each test is a good starting point for any case.

Thomas Daly is a local criminal and DUI defense attorney and has been practicing since 2013. Thomas practices primarily in Contra Costa County and is a member of the Contra Costa County Conflicts Panel and its advisory committee.