Does Probable Cause for Arrest Exist in Your DUI Case?

Whether Probable Cause for Arrest Exists in DUI Cases

Determining whether probable cause exited for an arrest in a DUI matter is an extremely important issue. If there was no probable cause for the arrest, then the entire case may be dismissed. In a DUI case, the arresting officer needs to establish probable cause that the driver of the vehicle is impaired either by alcohol or something other substance. The substance does not necessarily need to be illegal and can include such things as prescription drugs.

The first thing a police officer can use is the driving behavior of the driver. A lot of the time the police officer observes the bad driving behavior himself. Legal issues may arise if they did not see it themselves, for example, if some third party witness calls it in. The driving behavior can prove both the reasonable suspicion to stop the vehicle as well as probable cause to arrest the driver. Speeding, swerving, disobeying traffic signs and signals are just a few common driving behaviors that can count towards the probable cause for arrest.

The officer can also take into account the demeanor of the driver after the stop. Does the driver admit to drinking alcohol? Does the driver have slurred speech? Are their eyes blood shot? Does their motor function or movement seem impaired? Is the person nervous? The police officer can also take into account other simple observations like the presence of open containers in the car and whether or not the driver smells like they have been consuming alcoholic beverages recently.  He most damning of these is the defendant’s own statement that they have been drinking. Many people claim to have only had “a couple drinks” but that alone can be enough for a judge to find probable cause for a valid arrest.

Field sobriety tests are most often used by police officers to determine whether or not probable cause exists. These tests are meant to determine (with varying degrees of validity) whether someone is impaired. These tests can be either standardized or unstandardized. The unstandardized tests lack a scientific basis for reliability, meaning they have not been tested under lab conditions and may not be reliable. These tests may be challenged as invalid by a skilled attorney in court. Standardized tests have been subjected to lab conditions and have been scientifically examined for their reliability. These tests have been reviewed by the National Highway Traffic and Safety Administration (NHTSA) and are well regarded by almost all judges. These tests include the “9 step walk and turn,” “the one leg stand,” and the Horizontal Gaze Nystagmus (HGN). Although these tests are considered “reliable” indicators of someone’s impairment, a skilled attorney can challenge even these tests. The police officer observes how the driver does on these tests noting whether or not the driver exhibits “clues” of impairment. The attorney at Welch & Wright are well versed in these standardized tests and have successfully challenged their validity in court.

Refusing to do the field sobriety test is not enough by itself to establish probable cause. However, it is a factor that can be taken into consideration and can be deemed circumstantial evidence that the driver is impaired.

Under Va. Code 18.2-267(F), the law enforcement officer is required to inform a driver stopped for a suspected DUI that they have a right to take a Preliminary Breath Test (PBT). This breath test is usually performed by an Alka-Sensor, which is a small handheld device that the driver blows into to determine the driver’s probable Blood Alcohol Content (BAC) at that time. These machines are not nearly as accurate as establishing someone’s actual Blood Alcohol Content like the Intox EC/IR II breath machine at the police station or a blood draw. However, they are deemed accurate enough to establish probable cause to arrest. There is technically no required level of BAC that the driver has to reach on the PBT to establish probable cause. However, the presumptive level of intoxication in Virginia is .08. So this number has become almost a de facto limit to establish probable cause to arrest a driver for a DUI.