How Police Detect Drunk Drivers
In order to make a traffic stop for suspected DUI, law enforcement must have “reasonable suspicion” that a crime has occurred, is currently happening, or will happen soon. But what makes officers initially become suspicious?
Remember, the police do not have the right to just stop a vehicle based on a gut feeling or hunch. Rather, they must have a reason to pull someone over, often established by certain “cues” that indicate drunk driving.
Here are several driving patterns the National Highway Traffic Safety Administration (NHTSA) claims indicate an intoxicated motorist:
- Difficulties staying within a driving lane – Impaired drivers have trouble maintaining a proper lane position, either within one lane or switching lanes. Common examples include weaving across different lanes, swerving, drifting towards a side of the roadway, and making extremely wide turns.
- Judgment problems – Every time a person operates a vehicle, he/she must make a series of decisions while on the road. When drivers are intoxicated by alcohol, they often take more risks compared to sober motorists. Common examples include tailgating, making illegal turns, and otherwise driving erratically.
- Vigilance issues – Drivers must also maintain vigilance when operating a vehicle and properly react to various road conditions. Being intoxicated can lead to a lack of awareness. Common examples include slowly responding to or disobeying traffic signals and signs, using the incorrect turn signal each time a driver switches lanes, and driving in the dark without the headlights on.
- Acceleration and stopping problems – Drunk drivers typically have a hard time gaging speed and judging distances, resulting in acceleration and braking difficulties. Common examples include stopping a car well before or beyond a crosswalk or intersection, driving too fast or too slowly, or failure to maintain a consistent speed.
Once the police pull a driver over and notice other signs of intoxication like the odor of alcohol, slurred speech, delayed responses, as well as red and watery eyes, then officers have probable cause to make an arrest. They may gather further evidence of intoxication by making a driver perform a field sobriety test or take a breathalyzer test.