Reasonable suspicion and probable cause in a drunk driving stop

On Behalf of | Jan 18, 2024 | Brian E. Gordon, Criminal Defense, Daniel B. Hess, Jr., Gordon & Hess, PLC, Grand Haven, Grand Rapids, Kalamazoo, Muskegon |

Reasonable suspicion is a threshold that allows police officers to conduct a traffic stop if they reasonably believe that a person is committing, has committed or is about to commit a crime. This differs from probable cause, which is the higher standard for an arrest.

For suspected drunk driving, reasonable suspicion might arise from various observations. Erratic driving behaviors such as swerving, accelerating or decelerating rapidly, ignoring traffic signs or driving at night without headlights can all contribute to reasonable suspicion. Breaking traffic laws or a vehicle not meeting applicable codes, such as burned out headlights, can also lead to a traffic stop.

Determining probable cause after the stop 

During a traffic stop for suspected drunk driving, the officer’s observations of the driver are vital in establishing probable cause. Indicators of intoxication, such as the smell of alcohol, slurred speech, lack of coordination or bloodshot eyes, can all support the suspicion of drunk driving.

Once the stop is made, the officer may engage in a conversation with the driver, observe their behavior and potentially conduct field sobriety tests. These tests are designed to assess the driver’s physical and cognitive abilities, which can be impaired by alcohol consumption. Additionally, the officer might request a breathalyzer test to measure the driver’s blood alcohol content. 

If the officer can collect evidence that meets the standard of probable cause, they may arrest the driver for drunk driving. The driver would then need to work with someone familiar with these matters so they can develop a defense strategy. In some cases, lack of reasonable suspicion or probable cause may play an integral role in that strategy.