2012-06-15 10:45:17

State laws forbid driving while intoxicated, or DWI. The offense is also referred to in some jurisdictions as DUI (driving under the influence), OWI (operating while intoxicated), or OUI (operating under the influence). The enforcement of these laws involves searches and seizures subject to the Fourth Amendment.

The two types of DWI offenses are driving while impaired and driving while alcohol or drugs are present in the body. Driving while impaired requires proof that drugs or alcohol affected the operator’s physical or mental functions. Although no particular level of alcohol or drugs is proscribed, test results showing alcohol content in the body are evidence of impairment.

In contrast, driving while drugs or alcohol are in the body does not require proof of impairment. Instead, these laws require only that a forbidden level of alcohol be found in the body, as measured by breath, blood, or urine. Statutes often presume driving under the influence from 0.08 percent alcohol content in the blood. The 0.08 standard is a reduction from the formerly prevailing standard of 0.10. The lower standard exemplifies increasingly strict DWI statutes, which also have imposed greater punishments as social tolerance of drunk driving has decreased.

Fourth Amendment issues arise in DWI enforcement at two phases of DUI investigation: (1) the initial police–citizen encounter and (2) the detection of alcohol content in the suspect’s body.

The police–citizen encounter typically begins with a stop of a vehicle. Such a stop is a ‘‘seizure’’ under the Fourth Amendment. The Fourth Amendment permits police to stop a vehicle to detect drunk driving under three circumstances. First, police can stop the vehicle to investigate for drunk driving if they have reasonable suspicion to believe that the offense is being committed, as the U.S. Supreme Court held in Michigan v. Long, 463 U.S. 1032 (1983). This is the same legal basis used in Terry v. Ohio, 392 U.S. 1 (1968), to permit stopping a pedestrian.

Second, as the Supreme Court held in Whren v. United States, 517 U.S. 806 (1996), police can stop a vehicle for a traffic violation. Police can use the time spent in citing the motorist to look for indications of other crimes, including drunk driving. If reasonable suspicion of DWI arises, the officer may detain the driver further to investigate.

Third, police can establish checkpoints to find drunk drivers. checkpoints are allowed but must be fixed—roving patrols are not allowed—and must be of limited duration and nondiscriminatory in determining which motorists are stopped.

The Fourth Amendment also protects citizens from searches in the form of compulsory drug or alcohol tests, as the Court held in Schmerber v. California, 384 U.S. 757 (1966). Schmerber said that although police generally must obtain warrants, they can obtain blood without a warrant if they have probable cause, their method of obtaining the sample is reasonable, and a warrant cannot be secured before the alcohol in the body will dissipate.

The driver is required by most state laws to consent to these tests and provide samples of breath or blood. The theory of ‘‘implied consent’’ is that the state driving laws can condition the privilege of driving upon consent to such a test. In some states, the driver’s license of a motorist who refuses the test is subject to suspension or revocation. A more recent trend, adopted earlier in countries such as Canada and Australia, is to make refusal to submit to the test a crime.


Cases and Statutes Cited

  • Michigan v. Long, 463 U.S. 1032 (1983)
  • Schmerber v. California, 384 U.S. 757 (1966)
  • Terry v. Ohio, 392 U.S. 1 (1968)
  • Whren v. United States, 517 U.S. 806 (1996)

See also checkpoints (roadblocks); Drug Testing; Exemplars; Probable Cause; Skinner v. Railway Labor Executives, Association, 489 U.S. 602 (1989); Stop and Frisk