Signs of Impairment Police Look for When They Pull Drivers Over

When police pull over a driver on suspicion of DUI, they look for specific signs of impairment before making an arrest. Slurred speech, bloodshot eyes, and the smell of alcohol are common indicators. Officers also assess a driver’s behavior, coordination, and ability to follow instructions. Even small mistakes can raise suspicion and lead to further testing.

If you’ve been stopped for suspected DUI, knowing your rights is essential. A skilled DUI defense attorney in Naperville can make a difference in your case. Call our firm today at (630) 425-0250 to discuss your situation and explore your legal defense options in a free consultation.

Common Driving Behaviors That Raise Suspicion

Before pulling a driver over, police officers look for unusual or erratic driving behaviors that suggest potential impairment. Some of the most common signs that raise suspicion include:

• Swerving or drifting between lanes – An impaired driver may have difficulty maintaining a straight path, frequently veering between lanes or struggling to stay within road markings.
• Speeding or driving too slowly for conditions – Excessive speed or an unusually slow pace can indicate impaired judgment or delayed reaction times.
• Erratic braking or sudden stops – Unpredictable braking patterns, such as stopping too early or too late at intersections, are red flags for officers.
• Failing to use turn signals or making improper lane changes – Impaired drivers may forget to signal or change lanes unpredictably, putting themselves and others at risk.
• Driving without headlights at night – Forgetting to turn on headlights is a common mistake among drunk drivers, as alcohol can impair awareness and concentration.

If an officer observes these behaviors, they have reasonable suspicion to conduct a traffic stop and further investigate whether the driver is under the influence.

Physical Signs of Impairment During a Stop

Once a driver has been pulled over, officers assess their physical appearance and behavior for indicators of impairment. These may include:

• Bloodshot or glassy eyes – Alcohol and drugs can cause noticeable redness, irritation, or unusual pupil dilation.
• Slurred or slow speech – Impaired drivers may struggle to speak clearly or form coherent sentences.
• The odor of alcohol or drugs in the vehicle – If an officer smells alcohol or marijuana inside the car, they may use this as evidence of impairment.
• Difficulty answering questions or fumbling with documents – An intoxicated driver may have trouble understanding or responding to simple questions and may struggle to retrieve their driver license or registration.
• Poor coordination when exiting the vehicle – If an officer asks the driver to step out of the car, difficulty maintaining balance or unsteady movements may indicate impaired driving.

Police are trained to document these signs in their reports, which may later be used as evidence in a DUI case.

Behavioral Indicators of Impairment

In addition to physical signs, behavioral cues can also suggest that a driver is under the influence. These include:

• Confusion or inability to follow instructions – An intoxicated person may struggle to process and follow multiple directions at once.
• Aggressive or overly defensive responses – Some impaired drivers may become confrontational or overly argumentative with police officers.
• Delayed reactions or difficulty multitasking – Impaired individuals often display slowed reaction times and have trouble performing more than one task at a time.
• Excessive sweating or nervousness – While nervousness is natural during a traffic stop, excessive sweating, fidgeting, or paranoia may indicate impairment.

These behavioral indicators can support an officer’s decision to conduct further field sobriety testing or chemical testing.

Field Sobriety Tests and Chemical Testing

If an officer suspects impairment, they may ask the driver to perform field sobriety tests (FSTs). These tests help assess physical coordination and cognitive function. Some common FSTs include:

• Horizontal Gaze Nystagmus (HGN) Test – Officers check for involuntary jerking of the eyes, which can indicate intoxication.
• Walk-and-Turn Test – The driver must walk in a straight line, turn, and walk back while following specific instructions.
• One-Leg Stand Test – The driver must stand on one leg for a set amount of time without losing balance.

If a driver struggles with these tests, officers may request chemical testing, such as:

• Breathalyzer Test – Measures blood alcohol concentration (BAC) by analyzing breath samples.
• Blood or Urine Testing – If a breathalyzer result is unavailable or disputed, a blood or urine test may be required to confirm impairment.

Refusing field sobriety or BAC tests in Illinois can result in automatic license suspension due to the state’s implied consent laws.

Facing a DUI? Take the Right Legal Steps Now

Facing a DUI charge based on an officer’s observations can be overwhelming. Signs of impairment are often subjective, and factors like fatigue or medical conditions can mimic intoxication. Challenging the evidence against you may help reduce or dismiss the charges.

If you were pulled over and accused of driving under the influence, don’t face it alone. A strong legal defense can protect your rights and future. Contact our firm today to discuss your case and explore your options.