An officer must have “reasonable suspicion” that a driver did something illegal in order to pull over the driver. As a Pierce County DUI lawyer can advise you, it is often difficult to determine whether an officer had a reasonable suspicion of a DUI violation. This is especially true because the circumstances of every case are different, and rational people may realistically disagree on whether a particular set of circumstances constitutes reasonable suspicion.

In determining whether there was reasonable suspicion, a Pierce County DUI lawyer will look at whether the police officer actually witnessed any unlawful conduct. The U.S. Supreme Court held, in the case of Delaware v. Prouse, that it is not reasonable for an officer to stop a car just to check the driver’s license and registration, without any reasonable suspicion of illegal conduct. In the Prouse case, the officer testified that he stopped the car because he wasn’t doing anything else. The Court determined that this was not constitutional and established the following guideline for detaining a driver:

[E]xcept in those situations in which there is at least articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or occupant is otherwise subject to seizure for violation of law, stopping an automobile and detaining the driver in order to check his driver’s license and the registration of the automobile are unreasonable under the Fourth Amendment. [Delaware v. Prouse, 440 U.S. 648, 663 (1979).]

The crucial requirement is that the officer had an “articulable and reasonable suspicion” of illegal conduct. This is different than probable cause; probable cause governs the validity of an arrest, not just stopping a car.

The reasonable suspicion requirement is undoubtedly vague. In fact, DUI lawyers and the police both have difficulty trying to determine whether there was a reasonable suspicion of unlawful conduct in a given situation. However, the key distinction is that the lawyer has more time to sit back and assess the situation, whereas the officer often has to make a quick judgment out on the street. Nonetheless, an officer’s incorrect judgment does not excuse an unlawful DUI stop. Indeed, an experienced Pierce County DUI lawyer will concede the police officer’s good faith, but argue that the Constitution must still be obeyed.