Constitutional Considerations

There are a variety of constitutional considerations involved in impaired driving cases that appear at all stages of the case. Of particular focus on this page are the constitutional issues surrounding the reasonableness of the initial traffic stop, any testing done to the person stopped, the arrest, and statements made to the police. Most often at issue are the Fourth, Fifth, and Sixth Amendments to the U.S. Constitution. Some states may have increased levels of protection under their state constitutions with regard to some issues on this page, but this page lays out the constitutional protections involved in traffic stops as dictated by the U.S. Supreme Court.

Fourth Amendment to the United States Constitution

"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

Fifth Amendment to the United States Constitution

"No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation."

Sixth Amendment to the United States Constitution

"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defence."

Making the Stop

Reasonable Suspicion (“specific and articulable facts” to stop)

Terry v. Ohio, 392 U.S. 1 (1968).
The Supreme Court held in this case that an individual's Fourth Amendment rights are not violated if a police officer stops a person and frisks him or her without probable cause to make an arrest, so long as the officer is “. . .able to point to specific and articulable facts which, taken together with rational inferences from those facts, reasonably warrant that intrusion”--in other words, if the officer has a reasonable suspicion that the person either has committed or will commit a crime and may be dangerous to the officer.

Probable Cause to Make Traffic Stop 

Whren v. United States, 517 U.S. 806 (1996).
In this case, the Supreme Court ruled that any traffic violation committed by a driver is a legitimate legal basis to make a traffic stop, even if the stop was pretextual. The Court stated that "the officers had probable cause to believe that petitioners had violated the traffic code. That rendered the stop reasonable under the Fourth Amendment, the evidence thereby discovered admissible, and the upholding of the convictions by the Court of Appeals for the District of Columbia Circuit correct."


For cases involving sobriety (Michigan Dept. of State Police v. Sitz) and narcotics (City of Indianapolis v. Edmond) checkpoints and the Supreme Court's differing views on whether they are constitutional, see our Sobriety Testing and Evidence page.

Third Party/Anonymous Tips

Illinois v. Gates, 462 U.S. 213 (1983).
In this case, the Supreme Court rejected the Aguilar-Spinelli test for evaluating the validity of a search warrant or warrantless arrest based on a confidential informant or anonymous tip. In its place, the Court established a "totality of the circumstances" test, suggesting that the validity of each warrant should be examined case-by-case with all available context and not according to a rigid formula. 

Florida v. J.L., 529 U.S. 266 (2000).
In this case, the Supreme Court held that a police officer may not stop and frisk someone based solely on an anonymous tip that described the person's location and appearance but contained no details about any illegal conduct in which that person was participating or had participated. In its decision, the Court also stated that "the requirement that an anonymous tip bear standard indicia of reliability in order to justify a stop in no way diminishes a police officer's prerogative, in accord with Terry, to conduct a protective search of a person who has already been legitimately stopped."

Navarette v. California, 572 U.S. ___, 134 S. Ct. 1683 (2014).
In this case, police received a tip that a truck had recently run the caller off the road, and the caller gave a specific description of the make, model, color and license plate of the vehicle. Police found the truck and followed it for about five minutes, but did not observe any suspicious behavior. Nonetheless, they conducted a traffic stop and found thirty pounds of marijuana in the truck. At trial, the occupants of the truck argued that the tip was unreliable, but on appeal, the Supreme Court found the tip to be reliable and held that law enforcement does not need to personally observe criminal activity when acting upon information provided by an anonymous 911 call. Justice Scalia wrote a strong dissenting opinion in the case in which he argued that the tip was unreliable and that the Court’s opinion “serve[d] up a freedom-destroying cocktail consisting of two parts patent falsity.”

Brief Investigatory Detention (Reasonable suspicion for brief detention; traffic stops are an investigative detention)

Florida v. Royer, 460 U.S. 491 (1983).
In this case, the Court ruled that although it is legal to approach a person based on their behavior and nothing else, they cannot detain and/or search the person without a warrant. The Court used a totality of the circumstances test to determine whether the defendant in this case had been detained with his consent or not (and determined that he had not). The Court stated that "[t]his much, however, is clear: an investigative detention must be temporary and last no longer than is necessary to effectuate the purpose of the stop. Similarly, the investigative methods employed should be the least intrusive means reasonably available to verify or dispel the officer's suspicion in a short period of time."

Brown v. Texas, 443 U.S. 47 (1979).
The Court held that the application of a Texas statute to detain appellant and require him to identify himself without any reasonable suspicion that he had been engaged in criminal activity violated the Fourth Amendment. Accordingly, the Court held that the appellant could not be punished for refusing to identify himself and reversed his conviction.

Hiibel v. Sixth Judicial District Court of Nevada, 542 U.S. 177 (2004).
In this case, the Court held that a state law requiring a suspect to disclose his name in the course of a police investigation (in this case, a valid Terry stop) did not violate Fourth Amendment protections against unreasonable searches and seizures. The Court also held that the statute did not violate the suspect's Fifth Amendment right against self-incrimination, but left open the possibility of a scenario in which giving a name might be incriminating.

Arizona v. Johnson, 555 U.S. 323 (2009).
In this case, the Court held that police may conduct a pat down search of a passenger in a vehicle that has been stopped for a traffic violation, so long as the police have reasonable suspicion that the passenger is armed and/or dangerous.

Brendlin v. California, 551 U.S. 249 (2007).
In this case, the Court held that all occupants of a car are "seized" for Fourth Amendment purposes during a traffic stop, not just the driver.

Pennsylvania v. Mimms, 434 U.S. 106 (1977).
In this case, the Supreme Court held that a police officer may order a driver out of a car and conduct a pat-down of that person without violating the protections of the Fourth Amendment. In Maryland v. Wilson, 519 U.S. 408 (1997), the Court extended that rule to passengers in a vehicle, as well.


Arrest and Searches

In addition to probable cause or reasonable suspicion for the initial stop, the officers must have probable cause for the arrest.  Usually this means that the officers reasonably believe a felony has occurred or a misdemeanor occurred in their presence. A seizure occurs when a reasonable person would not feel free to leave or could not leave. In traffic cases, passengers are seized when the driver is seized. Fourth Amendment protections against unreasonable search and seizure are weaker during traffic stops than in other situations, especially within the confines of one's own home, because the Supreme Court has consistently treated car searches differently than other searches. However, police may search a vehicle incident to an arrest only if the suspect is within reaching distance of the passenger compartment or there is reason to believe evidence of the offense is in the vehicle. The following U.S. Supreme Court cases provide the basis for this line of reasoning:

Probable Cause

Brinegar v. United States, 338 U.S. 160 (1949).
In this case, the Supreme Court ruled that while officers must not always be proven factually correct by the results of a warrantless search, they must still possess a reasonable ground of suspicion to conduct the search, which is determined on a case-by-case basis. The Court emphasized that probable cause is the standard for arrests, not certainty of guilt beyond a reasonable doubt.

De facto arrest requires probable cause

Dunaway v. New York, 442 U.S. 200 (1979).
In this case, the Supreme Court emphasized that police must possess probable cause for an arrest and that the consequence of failing to make a proper cause was the exclusion of all statements by the arrestee, including his confession, despite the police having given a subsequent Miranda warning.


Weeks v. United States, 232 U.S. 383 (1914).
This case applied the exclusionary rule--the idea that the evidence from an unreasonable search cannot be admitted in court--to the federal government.

Mapp v. Ohio, 347 U.S. 643 (1961).
This case incorporated the provisions of the Fourth Amendment regarding unreasonable search and seizure and thereby made the exclusionary rule apply to state law enforcement as well as the federal government.

Search Incident To Arrest

Chimel v. California, 395 U.S. 752 (1969).
In this case, the Supreme Court held that in the course of an arrest at a person's home, police officers could not search the entire home without a warrant, but may search the area within immediate reach of the person.

United States v. Robinson, 414 U.S. 218 (1973).
In this case, the Court held that "in the case of a lawful custodial arrest a full search of the person is not only an exception to the warrant requirement of the Fourth Amendment, but is also a reasonable search under that Amendment."

Arizona v. Gant, 556 U.S. 332 (2009).
In this case, the Supreme Court held that police may search a vehicle incident to a recent occupant's arrest only if the arrestee is within reaching distance of the passenger compartment at the time of the search (in an effort to protect law enforcement) or it is reasonable to believe the vehicle contains evidence of the offense of arrest (in order to preserve evidence relating to the arrestee's crime).

Maryland v. King, 569 U.S. ___, 133 S. Ct. 1958 (2013).
In this case, the Court held that "when officers make an arrest supported by probable cause to hold for a serious offense and bring the suspect to the station to be detained in custody, taking and analyzing a cheek swab of the arrestee's DNA is, like fingerprinting and photographing, a legitimate police booking procedure that is reasonable under the Fourth Amendment."

Missouri v. McNeely, 569 U.S. ___, 133 S. Ct. 1552 (2013).
In this case, the Supreme Court rejected the theory stemming from Schmerber v. California that the natural dissipation of alcohol in the bloodstream was a per se "exigent circumstance" that permitted law enforcement to "search" someone in custody and take a blood sample without a warrant. Instead, the Court affirmed that exigency in impaired driving cases must be determined on a case-by-case basis. For an extended analysis of the case and a list of state court cases impacted by the Court's ruling in McNeely, see our page on the decision.

Riley v. California, 573 U.S. ___, 134 S. Ct. 2473 (2014).
In this case, the Supreme Court held that the warrantless search of a cell phone and seizure of its digital contents during an arrest is unconstitutional.

Birchfield v. North Dakota, 579 U.S. ___, 136 S. Ct. 2160 (2016).
In this case, the Court held that warrantless breath tests are permitted under the search incident to arrest doctrine but not warrantless blood tests (the latter having been established by McNeely), finding that blood tests are significantly more intrusive, implicate significantly more privacy concerns, and that their objective can be reached by other less intrusive means (namely breath tests).

Utah v. Strieff, 579 U.S. ___, 136 S. Ct. 2056 (2016).
In this case, the Supreme Court ruled that evidence found by police officers after illegal stops may be used in court if the officers conducted their searches after learning that the defendants had outstanding arrest warrants. In this case, police did not have reasonable suspicion to stop the defendant, but they stopped him and found an outstanding warrant for a traffic violation. The officers searched the defendant and found narcotics and drug paraphernalia. Although the stop was illegal, the Court said that the exclusionary rule did not apply because "the existence of a valid arrest warrant attenuated the connection between the unlawful stop and the discovery of the contraband."


Statements to Law Enforcement

Admissibility of incriminating statements, admissions, or confessions must be examined in terms of whether or not the encounter is an ordinary traffic stop or a custodial interrogation, which requires the procedural safeguards set forth in Miranda. Issues related to admission of laboratory results must be decided based on the confrontation clause analysis provided in Crawford, Bullcoming, and Melendez-Diaz.

Miranda Rights and Traffic Stops

Miranda v. Arizona, 384 U.S. 436 (1966).
In one of its landmark 20th century rulings, the Supreme Court ruled in this case that statements made by a defendant in the course of interrogation will not be admissible at trial unless the defendant was informed of his or her right against self-incrimination and his or her right to counsel before the interrogation. This case gave rise to the now ever-present Miranda warning, which does not have to follow an exact script, but must inform the defendant: (1) that they have the right to remain silent; (2) that anything the suspect does say can and may be used against them in a court of law; (3) that they have the right to have an attorney present before and during the questioning; and (4) that they have the right, if they cannot afford the services of an attorney, to have one appointed, at public expense and without cost to them, to represent them before and during the questioning.

Berkemer v. McCarty, 468 U.S. 420 (1984).
In this case, the Supreme Court held that, in the case of a person stopped for a traffic offense, Fifth Amendment protections pursuant to Miranda apply to them once they are in custody, but that custody is not usually found with a routine traffic stop. The Court stated that "a person subjected to custodial interrogation is entitled to the benefit of the procedural safeguards enunciated in Miranda, regardless of the nature or severity of the offense of which he is suspected or for which he was arrested. . . The comparatively nonthreatening character of detentions of this sort explains the absence of any suggestion in our opinions that Terry stops are subject to the dictates of Miranda. The similarly non-coercive aspect of ordinary traffic stops prompts us to hold that persons temporarily detained pursuant to such stops are not 'in custody' for the purposes of Miranda."

Pennsylvania v. Bruder , 488 U.S. 9, 109 S. Ct. 205 (1988).
In this case, the Supreme Court re-emphasized that ordinary traffic stops do not involve custody for the purposes of Miranda, and therefore, police do not need to inform those stopped for traffic violations of their Miranda rights unless taken into custody.

Note: for an analysis of the continuing relevance of the concept of voluntariness in criminal prosecutions, see It's Not Just About Miranda: Determining the Voluntariness of Confessions in Criminal Prosecutions by Professor Paul Marcus of William & Mary Law School, published in the Valparaiso University Law Review.

Chain-of-Custody and Other Evidentiary Issues

Crawford v. Washington, 541 U.S. 36 (2004).
In this case, the Supreme Court overturned its holding in Ohio v. Roberts and held that in order to admit prior testimonial statements of witnesses who have since become unavailable at trial, there must have been an opportunity to cross-examine that witness. In the Court's decision, Justice Scalia wrote that "[d]ispensing with confrontation because testimony is obviously reliable is akin to dispensing with jury trial because a defendant is obviously guilty."

Bullcoming v. New Mexico, 564 U.S. 647 (2011).
In this case, the Supreme Court held that the accused’s right is to be confronted with the analyst who made the certification or performed a test of the evidence and transcribed its results from the lab equipment used to conduct the test, unless that analyst is unavailable at trial and the accused had an opportunity to cross-examine that particular scientist before the trial.

Williams v. Illinois, 566 U.S. ___, (2012).
In this case, the Supreme Court ruled that an expert may base an opinion on the results of tests and experiments conducted by others, even when said expert has no firsthand knowledge of the testing procedure utilized, without violating the Confrontation Clause, distinguishing the Court's holdings in Crawford and Bullcoming.

Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009).
In this case, the Supreme Court held that it was a violation of the Confrontation Clause of the Sixth Amendment for a prosecutor to submit a chemical drug test report without the testimony of the person who performed the test. However, in its decision, the Court also stated that “[w]e do not hold, and it is not the case, that anyone whose testimony may be relevant in establishing the chain of custody, authenticity of the sample, or accuracy of the testing device, must appear in person as part of the prosecution's case. While... it is the obligation of the prosecution to establish the chain of custody, this does not mean that everyone who laid hands on the evidence must be called.”


State Case on Language Barriers and DUI

Rodriquez v. State No. S02A0412 (June 24, 2002). 
In this case, the Georgia Supreme Court held that a non-English-speaking defendant convicted of DUI was not denied equal protection or due process under the United States Constitution or the Georgia Constitution when the results of his blood-alcohol tests were admitted to trial, even though the implied consent warning required under Georgia's implied consent statute was not read or interpreted in a language that the defendant could understand.