Highlights of Post

  • Police are required to get a search warrant before taking a blood sample from a DWI suspect.
  • However, no search warrant is needed to obtain a breath sample from a  DWI suspect.
  • States cannot prosecute DWI suspects for refusing to submit to a warrantless blood test.  But states can criminally punish DWI suspects who refuse to take warrantless breath tests.


Some background information first:

The U.S. Supreme Court addressed whether police can obtain breath and blood draws from suspected DWI motorists without a warrant.

All states have Implied Consent Laws  that require drivers arrested for DWI to provide either a blood or breath sample to determine the blood alcohol concentration (BAC) in their system.  If a motorist refuses to provide a specimen, then his or her license is usually suspended.

North Dakota and Minnesota take their DWI laws a step farther.  In these two states (and a few others), a driver who declines to provide a blood or breath specimen after being arrested for DWI is charged with a separate offense—refusal to provide a chemical test.

So what’s the problem?

The Supreme Court heard three DWI cases from North Dakota and Minnesota to determine if search warrants are required before taking either a blood or breath specimen from DWI suspects.

In the first case, Birchfield vs. North Dakota, Daniel Birchfield crashed his car into a ditch in North Dakota and was arrested for DWI.  He declined to provide a blood sample as required by North Dakota law and was then charged with refusing to provide a chemical test.  He pleaded guilty to refusing to provide a blood sample and appealed arguing that the refusal law violated his Fourth Amendment right against unreasonable searches.

In Bernard v. Minnesota, William Robert Bernard, was arrested for DWI after he got his truck stuck in the St. Paul River while trying to pull a boat onto land.  Officers read Bernard the Minnesota Implied Consent warning notifying him that it is a crime to decline a chemical test.  Bernard refused to provide a breath sample and was prosecuted for refusing to provide a chemical test.  The trial court initially dismissed the charge, but on appeal the charge was reinstated and this appeal follows.

In Beyland v. North Dakota Dept. of Transp., Steve Michael Beyland, was stopped for driving erratically and exhibiting signs of intoxication.  He was arrested for DWI and police read him North Dakota’s Implied Consent law advising him it was a crime to not provide a chemical test.  To avoid being charged with the offense of refusing to provide a chemical sample of his BAC, Beyland gave a blood sample that showed his BAC was .25.  Beyland’s license was administratively suspended (similar to ALR Hearings) for two years and he appealed.   On appeal he argued his consent to provide the blood test was coerced because he consented only to avoid being charged with the offense of refusing to provide a chemical test.


ISSUE:  Do police need a search warrant before obtaining a breath or blood specimen from a motorist lawfully arrested on suspicion of DWI?

DWI Car Crashes
Supreme Court determined that police (government) have a strong interest in preventing harm caused by drunk drivers.  This outweighs privacy concerns from obtaining breath specimens from suspected DWI motorists.

To answer this question, the Court balanced the privacy concerns that blood and breath tests raise against the government’s legitimate interest in protecting the public from the dangers caused by drunk drivers.

The Court determined there is a difference between blood tests and breath tests for Fourth Amendment purposes.

The Court found that breath tests are non-invasive acts that are akin to blowing air into a balloon.  Also, breath tests provide only one bit of information–the alcohol concentration in a motorist’s blood stream.

However, unlike breath tests, blood tests are more invasive and require more Fourth Amendment protections since they require a needle to be stuck into the arm of a DWI suspect.  Moreover, blood samples convey potentially more information (such as medical illnesses, genetic traits, or other intimate medical data) than just the blood alcohol concentration in the driver’s system.

These distinctions were the difference in these cases.  The Court held that police do not need warrants to obtain breath tests from drunk drivers because they are non-invasive and communicate only the BAC in the driver’s system.  For this reason, warrantless breath tests are permissible  under the search incident to arrest doctrine (SITA).  The Court also found that because warrantless breath test searches are constitutional, then states can prosecute DWI drivers for refusing to submit to breath tests.

The result was different for blood draws.  As noted above, blood draws are more invasive and communicate more information than just the DWI suspect’s BAC.  This justifies requiring police to obtain a search warrant—absent exigent circumstances—before it can draw a DWI driver’s blood.

Further, states cannot criminalize a DWI driver’s refusal to give a blood sample because warrantless blood draws are unconstitutional.  For similar reasons, a DWI driver’s consent to submit to a blood draw under North Dakota’s Implied Consent law is coercive and invalid because the DWI suspect is threatened with criminal prosecution for declining to provide a warrantless blood draw.

The Court then reversed Birchfield’s conviction for refusing to provide a warrantless blood sample since it violated the Fourth Amendment.  But the Court affirmed Bernard’s conviction for not providing a breath sample because the state was allowed to take a breath sample without a warrant.  The Court also said that states can prosecute DWI suspects for refusing to take a breath test because warrantless breath tests are constitutional.

Finally, the Court reversed the judgment against Beylund to determine if Beylund’s consent was still valid in light of the Court’s rulings in this case.

What does this mean for you?

Police are allowed to take warrantless breath specimens from motorists arrested for DWI.  [NOTE—in Texas a person can still decline the breath test].  However, police must get a warrant—absent exigent circumstances—before they take a blood sample from a suspected drunk driver.

Also, on a related topic—people arrested for DWI should listen carefully to the Implied Consent warnings (Tex. Trans. Code 724.011)  given by the arresting officer.  If the warnings are incorrect or coercive, then it’s possible for your defense attorney to move to suppress the results of the breath or blood test.  But this is a very fact specific inquiry.  Talk to your DWI attorney to cover this issue before you decide to plead guilty.

Finally, don’t abandon hope if you are arrested for DWI.  It’s a difficult, embarrassing, and depressing situation to go through.  However, being arrested does not mean you are guilty.  Most importantly, you have rights and remedies if you believe the officer treated you unfairly or arrested you for DWI when you were actually sober.

PHONE:  210-733-7575

Author: Genaro Cortez

Hi! I am Genaro Cortez, a DWI Attorney in San Antonio, Texas. This blog provides information on frequently asked questions about DWI charges and criminal defense.