Police guidelines for reasonable suspicion of impaired driving or probable cause for a DUI stop are determined by the NHTSA (National Highway Traffic Safety Administrator). There are three main phases for police officers to observe when apprehending and processing a person for reasonable suspicion of a DUI. This article covers phase one.
Reasonable Suspicion DUI Stops: Observing The Vehicle in Motion
Pursuant to the 4th Amendment of the U.S. Constitution, every citizen has a constitutional right against unreasonable searches and seizures. This means that the police cannot stop your car or order you to pull over unless they have a reasonable suspicion that you committed or were about to commit a crime. There are times, however, when the police can in fact make a random stop that may seem unreasonable to you. For example, during what's known as "Amber" Alerts, the police can make you pull over and search your car without a warrant to check for a child that has been reported missing. Or they may order you to stop if your car matches the description of one that is connected to criminal activity.
Not necessarily every DUI defendant will be suspected of driving under the influence before they are pulled over. In other words, it is not always the case that a person is pulled over specifically for DUI, or because they were driving in a way that suggested they may be impaired. A DUI arrest is often made following a stop for a totally unrelated traffic infraction (such as speeding, improper lane usage, driving the wrong way down a one way street, running a red light, etc.). DUI arrests also have been known to be made after someone is pulled over for purely innocent behavior, such as in the Amber alert example above. In each of these situations, the officer will not suspect that you are impaired until after he has made contact and more observations of you.
On the other hand, there are times when the police may suspect you to be DUI before they even make contact with you. In such situations, you will be pulled over because the officer suspects you are too impaired to drive. The suspicion may arise as a result of the manner in which you were driving (such as weaving, veering, or other actions indicative of impairment), or based on a tip received, or because you were driving in an area and at a time where DUI's often occur. While normally the fact that you were speeding would not raise red DUI flags with the police, the police are more likely to think you could be driving drunk if done so at 4 a.m. down the Vegas strip.
Driving Patterns That Indicate Impairment
The NHTSA has a "DWI Detection Guide" that was written to help the police with detecting and arresting impaired drivers. The guide lists several things (what they call "cues") that they believe are suggestive of impairment, whether observed alone or together with other factors. The guide lists 24 indicators that the NHTSA tells the police they should look for in your driving pattern that could suggest you are DUI. The factors are broken up into four separate sections and are listed below:
- Problems Maintaining Proper Lane Position - Weaving, weaving outside the lane lane, straddling the lane line, swerving, making wide turns, drifting, almost hitting another vehicle or object;
- Speed and Braking Problems - stopping too far/short/jerky, accelerating or slowing for no apparent reason, varying speed, speed more than 10 M.P.H. slower then the speed limit;
- Vigilance (alertness) Problems - driving the wrong way down a one-way street, responding slowly to traffic signals, slow or failure to respond to police signals, stopping in lane without an apparent reason, driving at night without headlines on, signal issues (failure to signal, signaling inconsistent with action);
- Judgement Problems - Following too closely, Improper or unsafe lane changes, illegal/improper turns, driving on undesignated sections of the road, pulling over incorrectly when directed by police, display of inappropriate or unusual actions of belligerence, appearance of impairment.
Whether the police had suspicion reasonable enough to justify your stop is an issue you will definitely want to discuss with an experienced dui attorney who can help you defend your case.