Did you know during the 1930s the Potters Industries began producing tiny glass beads a fraction of a millimeter in diameter. The beads were used in the silver movie screens to give a much brighter image to the moviegoers. In an attempt to make traffic signs reflective, experiments were performed by sprinkling a layer of glass beads onto the wet paint of a traffic sign whereas most traffic signs were painted at this point in history.
In 1937, 3M Corporation developed a reflectorized tape for the purpose of road markings. One of the problems incurred was getting the adhesive to adhere to the road surface. At that point, they decided to use the sheeting to make signs reflective rather than use it for pavement markings. The problem with the 3M material, it was not very bright and they did not last long due to the weather elements. 3M then experimented by covering the beaded surface with a clear plastic film, which contained the glass beads. This process allowed for a constant retro reflective performance and gave the sheeting a smooth surface allowing it to be printed with translucent inks. This in turn produced a finished traffic sign.
3M first tried the engineer grade sheeting in Minneapolis which became the first commercial reflective sheeting product. It was used in the United Kingdom in 1947 and dominated the market in traffic signs for the next 25 years.
Type I Sheeting
Engineer Grade Prismatic – 16 mil, 5-7 year rating life. This sheeting can be used for noncritical traffic signage such as no parking, handicap or restrictive parking, or commercial signage. Engineer grade sheeting has a general night visibility of the approximately 500 feet.
Type III, IV, and X Sheeting
Hi Intensity Prismatic – 17 mil 10 year rating – meets ASTM D4956 – 09 Type III, Type IV and ASTM D4956 – 07 Type X. High Intensity sheeting is the most widely used type of sheeting for traffic signage meeting both Federal Highway Administration (FHWA) and most Department of Transportation (DOT) specifications. Its unique prismatic construction provides for vivid daytime colors and a higher level of retro reflectivity. This material is available in white yellow, red, orange, blue, green, and brown and generally has a nighttime visibility of approximate 1000 feet.
Type XI Sheeting
Diamond Grade DG3 Fluorescent Reflective Sheeting:
- Fluorescent Orange Sheeting – has a 22 mil and 3-year life rating.
- Fluorescent Yellow/Green – 22 mil 10-year life rating.
- Fluorescent Yellow – 22 mil 10-year life rating.
Diamond Grade Fluorescent Sheeting has fluorescent yellow green school signs that use both the prismatic and fluorescent technology. This technology gives you bright vivid fluorescent color during the day time and I highly reflective visibility at nighttime. This material provides excellent visibility at dawn, dusk and during inclement weather.
Type XI Sheeting
Diamond Grade DG3 – 12 year life rating. 3M’s Diamond Grade Cube sheeting is the brightest sheeting available. The material is 3x’s brighter than hi intensity sheeting. The nighttime visibility has an average of 1500 feet. It returns almost 60% of the light back to the driver through retro reflectivity. One of the benefits of the sheeting is that it overcomes the declining illumination from the newer type of vehicle headlights. This material also provides the level of illumination needed for older drivers. Although this sheeting is not widely used as of yet is gradually working its way into the market.
EC Film (Electrocut Overlay Film)
EC Film is a 3 mil acrylic colored film. EC film is placed over reflective sheeting to produce a colored background or copy. Transparency allows for the reflectivity to show through the film. EC film is used on overhead, tourist and directional signage.
What is Reflective Sheeting?
Retro reflective sheeting is a flexible retro reflective material primarily used to increase the nighttime conspicuity of traffic signs. The sheeting consists of retro reflective glass beads, micro prisms or encapsulated lenses sealed on the flexible substrate.
- ASTM standard D4956 – 11 a
- 3M Roadway Safety
- John Lloyd REMA.org.uk
- 3M Corporation – Traffic Control Materials Division