Traffic Stops and Roadblocks

Traffic stops and roadblocks fall under the Fourth Amendment’s protection against unreasonable searches and seizures because they limit our liberty of movement. A traffic stop or roadblock is valid when reasonable, and improperly obtained evidence may be suppressed from use in court against you.

Traffic Stops

A traffic stop normally occurs when a law enforcement officer signals a motorist to move to the side of the roadway and stop. The stop constitutes a seizure under the Fourth Amendment because it interferes with the motorist’s freedom of movement. In order for the stop to be valid under the Fourth Amendment of the United States Constitution, the officer must point to specific and articulated facts to support a reasonable suspicion or probable cause of criminal conduct.

Reasonable Suspicion Requirement

Although an officer may randomly stop a pedestrian to check for identification or purpose in the area, a random vehicle stop to check for a driver’s license or vehicle registration is not justified unless the officer has a reasonable suspicion that the driver does not have a license or that the vehicle is not registered. The officer must have a lawful reason or justification for stopping a motorist. A traffic stop that is not justified will not be valid and any evidence obtained by the officer from such a stop will not be admissible in court. Common justifications for traffic or investigative stops include:

  • Traffic violations
  • Defective equipment or equipment violations
  • Missing or defective license plates
  • Erratic driving behavior, such as reckless or drunk driving
  • Emergency response calls
  • Suspicious criminal activity

Pretext Stops

A pretextual traffic stop occurs when an officer uses the suspicion of a traffic violation as an excuse to stop a vehicle for another reason. Pretext stops may still be valid even if a reasonable officer would not have made the stop. Thus, the officer’s ulterior motive for making the stop may not be relevant in determining the validity of the stop. Still, many state courts will not blindly accept the officer’s pretextual traffic violation justification. For example, weaving and improper lane changes may not be sufficient to show the pretext of a traffic violation unless it is also shown that the motorist’s driving posed a safety issue to another vehicle.

Specific and Articulated Facts from Others

Normally, an officer’s own observations are accepted as sufficient to justify the stop. But what if the officer did not observe the traffic violation or the suspected criminal activity? What if the officer received the information from another person? An investigatory stop that is based upon facts obtained from a citizen informer rather than an anonymous tipster will more likely be found to justify the stop. Justification for the investigative stop increases if the facts from an anonymous tipster are corroborated.


Roadblocks or sobriety checkpoints are permitted under the Fourth Amendment so long as they are conducted in a neutral or non-arbitrary manner, their intrusion on motorists is limited, and they further an important governmental or public purpose. There is no requirement that an officer have a reasonable suspicion of criminal activity to justify a stop at a roadblock. Factors that determine whether a roadblock is neutral and does not overly intrude on motorists include whether:

  • Supervisory personnel or field officers make the decision to set up a roadblock
  • The roadblock is conducted according to neutral plans or guidelines
  • Cars are stopped randomly or are selected at the discretion of officers
  • The roadblock causes an unreasonable delay to motorists
  • The roadblock is clearly marked as a checkpoint
  • Officers conducting the checkpoint are properly trained and experienced
  • Advance notice is given to the public
  • Safe conditions are maintained

Roadblocks have been found to further a governmental interest in the following instances:

  • Catching and deterring drunk driving
  • Checking for vehicle or license registration
  • Addressing highway safety concerns, such as seatbelt law enforcement
  • Policing the border
  • Acquiring information on a recent violent crime in the area

A roadblock is not justified to obtain evidence of ordinary criminal wrongdoing or of drug crimes. Some state constitutions prohibit roadblocks and require officers to have an individualized suspicion to justify a vehicle stop.



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