How Profiling Works

Probable Cause Analysis

During a traffic stop, an officer can take several different actions that require different kinds of probable cause for them to be legal. Here we'll examine each step and break down the elements of probable cause.

  1. Pulling over a vehicle To legally pull someone over, an officer needs to have witnessed a traffic violation or another crime committed by someone in the car. He can also check the license plate number to see if the car is stolen or if there are arrest warrants out for the registered owner. If the car and its occupants fit a criminal profile, the officer can make a stop as long as he can describe specific factors that fit the profile. The race or skin color of the driver and occupants can't come into play, however.
  2. Questioning the suspect Once the officer pulls over a vehicle, he doesn't necessarily have to write a ticket. If the vehicle seems suspicious, the officer may just want to question the occupants, check their licenses against the department database and look inside the car. He can look at anything in plain view in the car. However, he does not have sufficient cause yet to enter and search the car. To do so would violate the Fourth Amendment protection against unreasonable search and seizure. However, if this preliminary investigation adds more weight to the officer's initial suspicion, he may have probable cause for an arrest and search. Again, this depends on the presence of specific factors in the profile, not just a "feeling," and race cannot be a factor. Image courtesy Once a suspect gives his consent, police officers can conduct a full search of his car.
  3. Consent to search If the actions of the suspects or the contents of their car raise further suspicions, the officer can ask the driver for consent to search the car. No one is ever required to say yes, but if they do, the officer needs no additional cause. The suspect has waived his Fourth Amendment rights, and the officer can conduct a full search. The officer is not required to tell the suspect that he can refuse consent (at least, not under federal law -- some states may have laws requiring this notification). This aspect is controversial because not everyone is aware of their right to refuse consent, and many people say yes out of fear or the feeling that the officer will do the search anyway.
  4. If consent is refused, the officer may detain the suspects for a reasonable amount of time. In 2005, the U.S. Supreme Court decided that using a drug-sniffing dog around the outside of a vehicle does not require a warrant nor any specific suspicion or probable cause, and does not violate the Fourth Amendment. If the dog "alerts" to the presence of drugs, that creates enough probable cause for a full search, without consent or a warrant. The "reasonable" amount of time provision is vaguely defined, although wait times up to 90 minutes have been allowed by federal courts [ref].
  5. Full search with probable cause The alert of a drug-sniffing dog, or seeing drugs or weapons sitting in plain sight inside the car are the most commonly accepted forms of probable cause. If the officer performs any of these actions without probable cause, then any evidence gathered as a result will not be allowed court. This could make it very difficult to successfully prosecute the suspect.