Understanding the nuances of traffic stops, especially drunk driving stops (which can result in some of the most significant consequences related to a traffic infraction), is crucial for drivers and law enforcement officers. Reasonable suspicion and probable cause play significant roles in these interactions, laying the groundwork for what officers can and can’t do.
Field sobriety and chemical tests may also influence this process and may or may not provide tangible evidence of impairment. Together, these elements (ideally) form a structured approach to identifying and addressing drunk driving, reducing road accidents and ensuring that due process is followed.
Reasonable suspicion
Reasonable suspicion is a legal standard that allows police to stop and briefly detain someone if they have a justifiable reason to believe that person is involved in criminal activity. This standard is lower than probable cause but requires more than a hunch. Behaviors such as swerving, speeding or breaking traffic laws may give an officer reasonable suspicion to conduct a stop and investigate further. This initial assessment is critical in preventing potential harm on the roads by allowing officers to intervene early.
Field sobriety tests
Once a driver is stopped, officers may conduct field sobriety tests if they suspect alcohol impairment. These tests are designed to evaluate a person’s balance, attention level and physical ability, which can be affected by alcohol consumption.
Components of the standardized field sobriety test include:
- Horizontal gaze nystagmus
- Walk-and-turn
- One-leg stand
While these tests can be subjective and influenced by various factors, they provide immediate, observable evidence of impairment that can support further action.
Chemical tests
Officers can administer chemical tests, typically involving breath, blood or urine samples for more definitive evidence of intoxication. The most common is the breathalyzer test, which measures blood alcohol concentration (BAC). Refusal to submit to these tests post-arrest can lead to immediate legal consequences, including license suspension, due to state implied consent laws.
Probable cause for arrest
Probable cause is a higher standard than reasonable suspicion and is necessary for making an arrest. It requires sufficient evidence to believe a person has committed a crime. In drunk driving cases, this could be based on the results of field sobriety and chemical tests, observed behavior and other factors. Probable cause helps to ensure that arrests are made on solid grounds, protecting individuals from unwarranted detention.
With all of this said, issues with any of these matters can potentially serve as a consideration in a defense strategy, so it’s critical to seek legal guidance about these matters if you’re ever charged with impaired driving.