Which factor is essential to establishing probable cause for a DUI observation?

• A. A hunch by the officer.
• B. Observable signs of impairment (e.g., slurred speech, unsteady balance, odor of alcohol) plus corroborating driving or field sobriety indicators.
• C. Only a confession from the driver.
• D. Only the results of a breath test after the fact.

Answer: (B)

Probable cause to continue a DUI investigation rests on objective signs of impairment observed by the officer, plus evidence from how the vehicle is being operated. When you notice impairment indicators like slurred speech, unsteady balance, or the odor of alcohol, those facts show the driver may be impaired. If those signs are coupled with driving indicators such as weaving, erratic lane position, or poor performance on field sobriety tasks, the combination builds a reasonable belief that the driver is intoxicated. That total, corroborated picture is what supports probable cause to detain further or arrest.

Relying on a mere hunch isn’t enough to justify an action, and a confession, while helpful, isn’t the sole basis for probable cause. Breath test results after the stop provide information about intoxication but don’t establish the initial probable cause to observe or stop in the first place.