Here’s What Those Tall Green Fins On the Highway Are Actually For

Have you ever driven along a highway or interstate and seen those weird green objects sticking up on top between lanes of traffic? Well, they’re not just cool roadway decor. These fins play an important role in creating a safer nighttime driving experience by reducing glare and improving lane awareness to prevent accidents.

What Are Headlight Shields?

Headlight shields, also known as oncoming headlight blockers, are devices installed between lanes of traffic to reduce the glare of headlights from oncoming vehicles. Especially useful in divided highways or multi-lane roads, these shields enhance nighttime driving safety by blocking intense beams of light from the opposing lane, preventing temporary “night blindness.”

This momentary loss of vision can be dangerous, particularly for drivers with increased light sensitivity, and headlight shields help mitigate this issue by creating a visual barrier between lanes.

What Do Headlight Shields Look Like?

Headlight shields are usually vertical panels that extend above the roadway divider, with a slight curve or angle designed to intercept the beam of oncoming headlights. They often resemble a row of slim, upright paddles or slats mounted along the center line or on a highway barrier.

While green and gray are the most common colors for headlight shields, they can also be seen in shades of blue or white, with colors chosen to blend with the surrounding environment or meet local visibility standards. Some shields are reflective, allowing them to be seen easily by both oncoming and same-direction drivers, helping improve overall road awareness and visibility.

Are There Other Traffic Devices Like Oncoming Headlight Blockers?

In addition to headlight shields, a variety of traffic control devices exist to help manage visibility and safety between lanes. Median barriers, like concrete Jersey barriers, are frequently installed to physically separate lanes of opposing traffic and can serve as a buffer against headlight glare. However, their primary purpose is crash prevention. Another common sight on highways is the installation of rumble strips along the edges of lanes. While not designed to block headlights, rumble strips alert drivers when they are veering off course, helping keep vehicles safely within their lanes.

In some regions, more advanced dynamic lighting systems are being implemented. These systems use technology such as adaptive headlights, which automatically dim high beams when oncoming traffic is detected. Additionally, road studs or “cat’s eyes” are reflective markers embedded in the road surface, helping to outline lane divisions in low-visibility conditions without needing to physically block oncoming lights.