Sobriety Checkpoints

Definition: Sobriety checkpoints are police stops, or checkpoints, where officers are set up on a roadway to randomly stop vehicles to check for impaired drivers. These are usually set up during times when impaired driving is known to happen, such as holiday weekends.

Executive Summary: Sobriety checkpoints, shown by some studies to be effective in combating impaired driving, are conducted in a fixed location at which police pull over vehicles according to a predetermined plan. If an officer’s preliminary encounter with the driver leads to a believe the driver may be under the influence of alcohol and/or drugs, the officer then conducts field sobriety tests that might result in a request for a breath test. The personal contact officers have with drivers increases the reliability of identifying hardcore alcohol-impaired drivers, as well as individuals driving with a suspended or revoked license due to an alcohol-related conviction.

In the U.S., law enforcement may not require breath tests of all drivers, only those for whom an officer has a reasonable suspicion of impaired driving. Not only do sobriety checkpoints provide officers a means to identify impaired drivers, the heightened media attention surrounding checkpoints can deter impaired driving in some instances by increasing drivers’ perceived risk of arrest.

More Detail: These detection techniques are commonly targeted to specific areas and times that studies have shown the probability of a DUI apprehension is highest (i.e. after bars and restaurants close in the entertainment section of town, or over holiday weekends such as Memorial or Labor Day, etc.).

One limitation of sobriety checkpoints is the lack of time to view driving behavior to determine suspicion of impaired driving. Therefore, most of the officer’s decision to formulate suspicion of impairment depends on the few moments of interaction and conversation with the driver.

States may differ in their laws regarding stops and seizures so it is best for law enforcement to consult with the state statute and relevant case law. An officer can also check with a prosecutor regarding the conditions that need to be observed for this type of stop to be legal, and for evidence gathered to be admissible in court. In most cases, where such stops are lawful, set conditions must be observed and later proven by law enforcement in court. For instance, some states require public disclosure that such stops are being made in advance of the checkpoints actually being set up. Other states require that every automobile be stopped versus, for example every third vehicle being stopped. Some states require that stops be brief and not last longer than a specific period of time.

These mobilizations work best when prosecutors and court officials have been given sufficient notice to prepare for the higher than ordinary influx of DUI cases that occur following such campaigns. It does little good to arrest large numbers of DUI suspects only to have their cases delayed, dismissed or pleaded down because the city prosecutor or town judge was overwhelmed due to lack of preparation time. Calendars should be adjusted, and resources identified in order to meet the influx of cases generated by the campaign.

Not all states conduct sobriety checkpoints. A recent study of state police departments found that 13 states do not currently conduct sobriety checkpoints. Of these, 12 states consider checkpoints to be contrary to state law (Fell 2003).

Thirty-seven states, plus the District of Columbia, confirmed their use of sobriety checkpoints, though 13 said that limited resources lead to checkpoints being conducted on an infrequent basis (Fell, 2004). Fortunately, studies have shown that checkpoints can be completed successfully with a limited number of officers. Surprisingly, increasing the number of police officers at a checkpoint does not necessarily increase the efficacy of their use (Fell, 2003).

A systematic review of 15 studies conducted for The Community Guide to Preventive Services concluded that strong evidence exists for the effectiveness of sobriety checkpoints in decreasing the incidence of DUI (CDC, 2002). These checkpoints were found to decrease fatal crashes between 20% and 26%, and property damage collisions by an average of 24% (Elder et al, 2002). While sobriety checkpoints have been shown as effective, one study found that only 38% of drivers with a BAC of 0.08 or above were detected during a routine sobriety checkpoint (Wells, 1997), indicating the challenges law enforcement have in consistently detecting hardcore and other impaired drivers.

Stopping a vehicle, albeit briefly, constitutes a “seizure” under the Fourth Amendment to the U.S. Constitution and, thus must be reasonable and with probable cause. In evaluating the constitutionality of a checkpoint, courts generally require that the procedures utilized curtail the unbridled discretion of the officer in the field. See Delaware v. Prouse, (1979) 440 U.S. at 662, 99 S.Ct. 1391. The Louisiana Supreme Court decision in State v. Jackson764 So.2d 64, 72-73, (La., 2000) illustrates the considerations that courts generally employ to determine the validity of sobriety checkpoints.

They are as follows:

  1. The location, time and duration of a checkpoint, and other regulations for operation of the checkpoint should be established (preferably in written form) by supervisory or other administrative personnel rather than the field officers implementing the checkpoint;
  2. Advance warning to the approaching motorist with signs, flares and other indications to warn of the impending stop in a safe manner and to provide notice of its official nature as a police checkpoint;
  3. Detention of the motorist for a minimal length of time; and
  4. Use of systematic non-random criteria for stopping motorists.


Suggested Audience: Enforcement, Judges


Works Cited:

  • Fell, J.C.; Lacey, J.H.; Voas, R.B. Sobriety checkpoints: evidence of effectiveness is strong, but use is limited. Traffic Inj Prev. 5(3):220-227, 2004.
  • Fell, JC; Ferguson, SA; Williams, AF; Fields, M. Why are sobriety checkpoints not widely adopted as an enforcement strategy in the United States? Accident Analysis & Prevention 2003; 35:897-902.
  • CDC – Effectiveness of Sobriety Checkpoints for Preventing Alcohol-Involved Crashes (2002)
  • Elder, RW; Schults, RA; Sleet, DA; Nichols JL; Zaza, S; and Thompson, RA. Effectiveness of sobriety Checkpoints for Reducing Alcohol-Impaired Crashes. Traffic Injury Prevention 2002; 3:266-274.
  • Wells J. Greene M, Foss R, Ferguson S, Williams A. Drinking Drivers Missed at Sobriety Checkpoints. J Studies Alcohol 1997: 58; 513-517.

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