The Fourth Amendment and Driving Under the Influence Investigations
By Attorney Darlene Bagley
Many individuals stopped and investigated for driving under the influence
are not aware of the constitutional rights they retain throughout the
investigation. The purpose of this article is to inform the reader
of what these rights are and to discuss where the line is drawn between
voluntary tests and tests mandated by the Express Consent law in Colorado.
When a law enforcement officer stops an individual suspected of driving
under the influence (“DUI”), the initial request is for driver's license,
registration, and insurance documents is typically followed by a request
for the driver to exit the vehicle for the administration of standard
field sobriety tests (“SFSTs”)—commonly known as roadside tests—and
a portable breath test (“PBT”)—a breath test conducted at the scene
using a hand-held breathalyzer. However, these tests implicate the
Fourth Amendment as the individual must agree or consent to take these
tests or the administration of the tests is unconstitutional.
Colorado courts have long held that the administration of roadside
tests implicates the Fourth Amendment as it is a constructive “search” of
a person's abilities and faculties.1 Consent
is a legally recognized exception to the warrant requirement and essentially
amounts to the individual waiving his Fourth Amendment protection from
warrantless searches and seizures. If a driver agrees to the administration
of SFSTs, then generally the results of those tests will be admissible
as evidence against him at a later DUI trial. However, when law enforcement
asks (or instructs) him to perform the tests, the driver has the constitutional
right to say no.
Likewise, the submission to a portable breath test must be voluntary.
In fact, Colorado law expressly requires that law enforcement instruct
those individuals whom they suspect of driving under the influence
that they may either refuse or agree to submit to the PBT.2 The
driver has the constitutional right to say no to the administration
of the PBT, and evidence of the driver's decision to decline the administration
of the PBT is inadmissible at a later jury trial against him.3
If a law enforcement officer determines that he has probable cause
to arrest a driver for DUI and so arrests the driver, he is then required
to advise the driver of the Express Consent law. Unlike with the SFSTs
and the PBT, there is no constitutional right to refuse to comply with
the Express Consent law. The Express Consent law in Colorado states
that “A person who drives a motor vehicle upon the streets and highways
and elsewhere through this state shall be required to take and complete,
and to cooperate in the taking and completing of, any test or tests
of the person's breath or blood for the purpose of determining the
alcoholic content of the person's blood or breath when so requested
and directed by a law enforcement officer having probable cause to
believe that the person was driving a motor vehicle in violation of
the prohibitions against DUI, DUI per se, DWAI, habitual user, or UDD.”4 If
the driver fails to take or complete, or to cooperate in the completion
of, the chemical test required by the Express Consent law, the failure
shall be deemed to be a refusal.5
Drivers must be aware of the constitutional rights they have when
under investigation for DUI and be confident of their ability to invoke
them when applicable and/or necessary.
1. People v. Carlson
, 677 P.2d 310, 317 (Colo. 1984).
2. §42-4-1301(6)(i)(I),
C.R.S. (2008).
3. §42-4-1301(6)(i)(III),
C.R.S. (2008).
4. §42-4-1301.1(2)(a)(I),
C.R.S. (2008) (emphasis added).
5. §42-4-1301.1(2)(a)(II),
C.R.S. (2008).
