When an oncoming car has its high beams on, you should look toward the right edge of your lane rather than directly at the headlights. Most states require drivers to dim high beams within 500 feet of an oncoming vehicle, but you can’t control what the other driver does. What you can control is where your eyes go, how you maintain your lane, and how quickly you recover your vision afterward.
Why High Beams Cause Temporary Blindness
Your eyes adapt to darkness by relying on light-sensitive cells called rods. When a bright light source like high beams floods your retina, it depletes the photopigment in those cells, essentially “bleaching” them. The reduction in vision is immediate, but recovery isn’t. Research measuring visual recovery after intense light exposure found that it takes roughly 2 to 3 seconds for healthy eyes to regain the ability to see even high-contrast objects like a white lane marking on dark pavement. For low-contrast objects, like a pedestrian in dark clothing, recovery stretches longer.
Those seconds matter more than most people realize. At highway speeds, a driver travels about 27 meters (roughly 90 feet) per second. A study published in Photonics calculated that a nearsighted driver dazzled by a flash at 100 km/h would travel over 33 meters farther than a driver with normal vision before spotting a low-contrast object. Even drivers with perfect eyesight are effectively blind for a meaningful stretch of road.
How to Keep Your Lane During Glare
The single most effective thing you can do is shift your gaze to the right side of the road. The solid white line on the shoulder, sometimes called the fog line, serves as your guide. Caltrans specifically recommends using this line to maintain lane position when visibility drops. By focusing on it with your peripheral vision rather than staring at the oncoming headlights, you avoid the worst of the photopigment bleaching and keep a reference point for steering.
Beyond shifting your gaze, slow down. Reducing your speed buys you more reaction time if your vision takes a couple of extra seconds to recover. Avoid the instinct to look directly at the headlights to “figure out” where the other car is. Your peripheral vision is actually more sensitive in the dark than your central vision, so you’ll track the oncoming vehicle better by not staring at it.
The 500-Foot Dimming Rule
In most U.S. states, drivers are legally required to switch from high beams to low beams when within 500 feet of an oncoming vehicle. Virginia’s statute is typical: it requires low beams “so aimed that glaring rays are not projected into the eyes of the oncoming driver.” Many states use this same 500-foot threshold, and some also require dimming within 200 to 300 feet when following another vehicle.
If someone isn’t dimming, you might instinctively want to flash your own high beams as a reminder. In most states, a quick flash is legal and courts have generally treated it as protected expression under the First Amendment. However, some states, including California, specifically prohibit flashing high beams at oncoming traffic because it can temporarily blind the other driver too. A single brief flash is different from holding your high beams on in retaliation, which creates danger for both of you.
Why Some Cars Seem Worse Than Others
Not all high beams produce the same glare. Three factors determine how blinding an oncoming vehicle feels: beam aim, mounting height, and bulb type.
- Mounting height: Headlights on SUVs and trucks sit higher than those on sedans. Research from NHTSA found that higher-mounted headlamps tend to produce greater discomfort glare for drivers in lower vehicles. Federal rules allow headlamp mounting heights between 56 and 137 centimeters (roughly 22 to 54 inches), which is a wide range.
- Beam aim: NHTSA identified headlamp aim as the single biggest factor in how much light reaches an oncoming driver’s eyes. A halogen headlight that’s aimed even slightly upward can produce glare as severe as a brighter HID headlight that’s properly aligned. Misalignment happens gradually from potholes, heavy cargo, or wear.
- Bulb technology: LED and HID headlights produce a whiter, more intense light than older halogen bulbs. Even on low beam, these can feel like high beams to oncoming drivers, especially from taller vehicles aimed at sedan windshield height.
This means that some of the “high beam” encounters you experience may actually be low beams from a lifted truck with misaimed headlights. The glare effect on your eyes is the same regardless.
Yellow Night-Driving Glasses Don’t Help
Yellow-tinted “night driving” glasses are widely marketed as a solution for headlight glare. They don’t work. A study published in JAMA Ophthalmology tested yellow-lens glasses in a driving simulator and found they did not improve pedestrian detection at night, with or without headlight glare present. The researchers noted that wearing the glasses may have slightly worsened detection performance, though that finding wasn’t statistically significant. The study’s authors specifically recommended against eye care professionals advising patients to use them.
The reason is straightforward: yellow lenses reduce the total amount of light reaching your eyes. At night, when visibility is already limited, cutting light intake makes it harder to see objects in the road. The slight contrast boost the tint provides in daylight conditions doesn’t translate to nighttime driving, where the problem isn’t contrast but overall darkness punctuated by intense point sources of glare.
Adaptive Headlights Are Changing the Problem
Adaptive driving beam (ADB) headlights use cameras and software to keep high beams on while carving out shadows around oncoming vehicles and pedestrians. This gives the driver maximum road illumination without blinding anyone else. The technology has been available in Europe for years, and in February 2022, NHTSA issued a final rule amending U.S. headlight standards to allow ADB systems on new vehicles sold in the United States. This rule satisfied a requirement in the Bipartisan Infrastructure Law more than a year and a half ahead of schedule.
As more vehicles adopt ADB, the problem of oncoming high-beam glare should decrease. But adoption takes time, and the technology only helps when both your vehicle and the oncoming one are equipped. For now, the fundamentals remain: look right, slow down, and give your eyes time to recover before making any sudden steering or braking decisions.