The Secret Car Button Almost No One Knows About—And Why It Can Make Night Driving Safer

Have you ever noticed a small button in your car that you rarely use and wondered what it actually does?

One of the most useful controls for nighttime driving is often found on the rearview mirror. It may look insignificant, but it can reduce the glare from headlights behind you and make it easier to see the road.

🌙 The small tab on your rearview mirror

If your car has a traditional manually adjustable rearview mirror, look underneath it for a small tab or lever.

During the day, the mirror can remain in its normal position.

At night, flipping the tab changes the angle of the reflective surface. Headlights from vehicles behind you are then directed away from your eyes, reducing the harsh glare while still allowing you to see the vehicle behind you.

It’s sometimes called the day/night or anti-glare mirror.

What if your car doesn’t have a tab?

Many newer vehicles use an automatically dimming rearview mirror instead.

These mirrors typically contain light sensors that detect bright headlights behind you and automatically darken the reflective surface. Some vehicles also have electronically controlled side mirrors with similar anti-glare functions.

Why it matters at night

Bright headlights can temporarily make it harder to see the road, particularly on dark or poorly lit roads.

Reducing glare can make nighttime driving more comfortable and can help you maintain a clearer view of what’s ahead.

One important point: this isn’t a secret button that makes night driving completely safe. Keep your windshield and mirrors clean, adjust your mirrors correctly, and slow down when visibility is poor.

And before using any unfamiliar control in your vehicle, check the owner’s manual—features and controls vary considerably between makes and models.