Determining Reflectivity

Determining Sign Reflectivity

Retroreflective sheeting- How do I choose what type is best for my signs?

Many of the traffic signs, safety signs, and parking signs available on TrafficSign.com are available in reflective aluminum. Much like coated aluminum, reflective aluminum won’t rust, crack, or chip and helps increase visibility during the night, in low-light settings, and during times of inclement weather.

Not all reflective aluminum is created equally. When we describe how reflective something is, we talk about its reflectivity. Reflectivity is a simple concept and refers to how efficiently a material redirects light back to its original source. In other words, the reflectivity of a sign has great impact on how easily a sign can be read. Reflectivity is so crucial for visibility that the Federal Highway Administration mandates that all regulatory traffic, traffic warning, object markers, and guide signs must be reflective.

As mentioned above, not all materials have the same grade of reflectivity, and different kinds of reflective sheeting are better suited for different situations. Because of this, it’s helpful to learn a little more about the different reflectivity grades.

Diamond grade sheeting is the most reflective grade available. It is the top choice for use on roadways due to providing maximum visibility from the farthest viewing distances. Diamond grade sheeting is also the most durable, which makes these signs a worthwhile investment.

Signs made with diamond grade sheeting can often be seen from as far as 1,500 feet away. They are also 10 times brighter than standard engineering grade sheeting. This makes diamond grade sheeting the optimal choice for hazardous areas and high-traffic intersections.

High intensity prismatic retroreflective sheeting (HIP sheeting) isn’t as reflective as diamond grade sheeting. It is typically used on official traffic signs, like the ones you might see around your community. HIP sheeting is about three times more reflective than engineering grade sheeting. Signs made with HIP sheeting can be seen from about 1,000 feet away.

Engineering grade sheeting (EG sheeting) is most often used for parking and property signs. Signs that are made from EG sheeting can usually be seen from about 500 feet away.

See the chart below for a breakdown of the different kinds of retroreflective sheeting:

To learn more about identifying different kinds of retroreflective sheeting, please visit the Federal Highway Administration’s traffic sign retroreflective sheeting identification guide.

For more information on retroreflective sheeting designations and minimum maintained retroreflectivity levels, see Section 2A.08 of the Federal Highway Administration’s Manual on Uniform Traffic Control Devices.