3M's 1.9 index optics are effective at directing light back to its source in dry conditions. But add water and the performance of these optics drops off dramatically. That's because water refracts—or bends—light, changing the angle needed to reflect light back to where drivers can see it.

3M scientists have found that beads with a 2.4 refractive index compensate for the refractive properties of water, making them ideal for reflecting light back to its source under wet conditions. So to ensure that 3M pavement markings perform in all weather conditions, 3M blends both dry- and wet-reflective beads together in our paints and tapes. The result: durable, high performance products that deliver optimal visibility in all weather conditions.

Unlike the glass beads typically found in conventional pavement markings, 3M all-weather markings feature tough, long-lasting microcrystalline ceramic beads. Through a unique combination of materials and processes, 3M has found a way to build strong microcrystalline structures into all 3M high index optics. These tough, durable optics have proven themselves on roadways all over the world, starting with the original 380 tape in the 1990s. Since then, 3M microcrystalline ceramic beads have evolved into brighter and even higher index versions with outstanding performance and durability.

How do we know these high index optics will hold up under real-world conditions? 3M scientists have literally sandblasted both 3M microcrystalline and conventional glass beads. The resulting microscopic images (see left) tell the story. Conventional 1.9 index glass beads lose nearly all of their "relative reflectivity" when exposed to the abrasive effects of sand, while 3M's microcrystalline ceramic beads retain nearly 75% of their initial reflectivity.

Pavement markings are constantly exposed to the highest forms of abuse: sand, salt and dirt; blistering sunlight and heat; rain, snow and ice. Not to mention the crushing force of thousands of speeding cars and trucks. No pavement markings can withstand these forces forever, of course, but 3M markings are designed for maximum durability.

From multi-year warranted tapes to all-weather paints that can last up to twice as long as other roadway paints, 3M roadway markings are designed for maximum road presence. This means they will continue to work like they're supposed to work, helping to keep lanes, edge lines and other roadway markings bright and visible—whatever your geography or environment, from the subzero temperatures of northern Minnesota to the heat of west Texas.

Adhesives have been a core 3M technology for nearly 100 years. So it's no wonder that 3M products are known worldwide for their ability to stick— and stay stuck. Our adhesives expertise has allowed us to create a line of superior-performing roadway markings that need no surface preparation during the 3M Climate Guide-defined application season. Some products can even be applied during early spring and late fall. The result? A significantly extended striping season, faster and easier application, and greater productivity all-around for your roadway crews and contractors.