The single most effective way to protect yourself against impaired drivers is to increase your following distance and physical space from any vehicle behaving erratically. But that one move is part of a broader set of habits that dramatically lower your risk. In 2022, alcohol-impaired driving killed 13,524 people in the United States, accounting for 32% of all traffic fatalities. Many of those deaths were sober drivers, passengers, and pedestrians who simply crossed paths with the wrong car at the wrong time.
Spot an Impaired Driver Before It’s Too Late
The National Highway Traffic Safety Administration identifies four categories of driving behavior that signal impairment: lane position problems, speed and braking problems, vigilance problems, and judgment problems. Knowing what these look like gives you a few extra seconds to react.
Lane position is the biggest giveaway. An impaired driver will weave within their lane, drift gradually toward the shoulder or center line, straddle lane markings, or swerve abruptly back into position after realizing they’ve drifted. You might also see unusually wide turns, where the vehicle swings far outside the normal arc of a turn. Any of these behaviors predicts impairment roughly 50 to 75% of the time, according to NHTSA research used to train law enforcement.
Speed irregularities are the second major clue. Watch for a vehicle that accelerates and decelerates for no visible reason, varies speed unpredictably, travels more than 10 mph below the speed limit, or brakes in a jerky, erratic pattern. These behaviors predict impairment 45 to 70% of the time. A driver doing any combination of lane and speed errors is very likely impaired.
Create as Much Space as Possible
Distance is your best defense. If you’re behind a suspected impaired driver, increase your following distance well beyond the normal recommendation. The Federal Motor Carrier Safety Administration advises at least one second of gap for every 10 feet of vehicle length at speeds under 40 mph, with an additional second above 40 mph. When you suspect impairment, double that distance at minimum. The extra space gives you time to brake or steer around a sudden stop, swerve, or lane change you can’t predict.
If the impaired driver is behind you, change lanes or pull off the road safely and let them pass. Do not speed up to create distance, because that introduces its own risk. If you’re on a two-lane road with no room to pull over, slow down gradually and move as far right as you can to let them overtake you. The goal is always the same: get the impaired vehicle out of your immediate vicinity.
Choose the Right Lane on Highways
Wrong-way drivers, who are overwhelmingly impaired, tend to enter freeways through exit ramps and end up in what they perceive as the “right” lane. On your side of the road, that means the left lane or carpool lane. The Arizona Chapter of the National Safety Council notes that many wrong-way collisions happen in the left lanes for exactly this reason.
When driving late at night on divided highways, staying in the right or center lanes gives you a wider buffer from any vehicle traveling the wrong direction. If you see a wrong-way driver or a highway warning sign alerts you to one, move right immediately and reduce your speed.
Know When the Risk Is Highest
Impaired driving crashes are not evenly distributed throughout the week. NHTSA data shows that between midnight and 3 a.m., 55% of drivers involved in fatal crashes were alcohol-impaired. That’s more than 10 percentage points higher than any other time window and roughly twice the overall average. Weekends are significantly worse: drivers in fatal crashes from Friday evening through early Monday morning were twice as likely to be impaired (31%) compared to weekday crashes (16%).
This doesn’t mean you should never drive late on weekends, but it does mean those hours call for heightened alertness. Scan farther ahead, keep your speed moderate, and stay in the right lanes on highways. If you’re leaving a bar, concert, or sporting event at the same time as large crowds, expect that some drivers around you are impaired and drive accordingly.
Pause at Green Lights and Intersections
Intersections are where impaired drivers cause some of the most devastating crashes, because running a red light at full speed creates a T-bone collision with almost no warning. When your light turns green, pause for one to two seconds before entering the intersection. Use that moment to look left, right, then left again. This brief delay costs you almost nothing but can save your life if someone barrels through a stale red.
The same habit applies at stop signs, especially late at night. Even when you have the right of way, treat every intersection as if someone might not stop. Impaired drivers frequently miss stop signs entirely or brake far too late.
Report the Driver
Calling 911 protects not just you but every other driver on the road. Pull over or have a passenger make the call. Dispatchers will ask for your location first, so note the road name, direction of travel, and any nearby landmarks or mile markers before you dial. Then provide as much detail as you can about the vehicle: color, make, model, license plate number (even a partial plate helps), and the direction it’s heading. Describe the specific behavior you observed, whether that’s weaving, wrong-way driving, or erratic speed changes.
Don’t follow the impaired driver to get more information. Once you’ve reported what you know, let law enforcement handle it.
Wear Your Seatbelt and Stay Sober Yourself
This sounds obvious, but seatbelt use remains the single most effective way to survive any crash, including one caused by an impaired driver. In alcohol-related fatal crashes, a large proportion of victims who died were unbelted. A properly worn seatbelt reduces your risk of fatal injury by about 45% in a car and 60% in a truck or SUV.
Staying sober yourself matters because your reaction time is what stands between spotting an erratic vehicle and avoiding it. Even one or two drinks slow your ability to process the warning signs described above and execute the evasive maneuvers that keep you safe. If you’ve been drinking, you lose the very defensive advantage that protects you from other impaired drivers on the road.