The need for road markings of all types is becoming increasingly important in controlling the position of moving traffic into orderly lanes and in showing road users where they can and cannot be on highways.
White lines are still the major part of road markings and make an important contribution to road safety, particularlyat night, and in this context the ability of the road markings to reflect light from the vehicle back to the driver (known as retro-reflectivity) has become increasingly important and is now specified, together with the very important properties of a road marking or line: durability, luminance ("brightness") and skid resistance.
Road marking media and paints
Recent advancements in road marking have led to the addition of glass beads to road marking media. Starbead® standard glass beads are a major factor in increasing road safety in an economical manner. Thanks to the beads' retro-reflective action at night, a vehicle's headlight beam is returned to the driver's eye. The microspheres not only multiply the visibility of the road markings at night, but also increase the markings' durability. Starbead® glass beads are used as a drop-on agent and as premix beads for roadmarking materials.
Road marking equipment
The LineLazer® was first designed as a walk-behind line striper which delivers sharp, consistent lines with 2 to 4 times more productivity than the old stand-by air spray units, removing overspray and waterbase striping problems. The LineLazer® is now available in several models, including a ride-on sprayer.
The RoadLazer®, Graco’s patented hydraulic truck-mounted striping system, is designed with 300 Series Grade wetted parts, offering 100% chemical compatibility with all traffic paints including today’s newer pH-sensitive waterborne paint formulations. This airless striping technology produces precise lines every time, without excessive overspray or the fuzzy, uneven lines normally associated with air spray striping. It also ensures faster drying times, consistent paint thicknesses and waterbase lines that look like tape. The RoadLazer applies reflectorized airless lines at highly productive speeds – up to 10 mph (16 kph). Line widths to 36 in (914 mm) are possible with the optional third gun kit. And simultaneous dual-color striping is no problem. Loading and unloading is easily done by one person without forklifts or overhead cranes.
The process of "road marking"
Traditionally, road marking is achieved by applying a coating to the road surface. This has been in the form of constantly improving and evolving paints which are either solvent or oil based.
A relatively new evolution is the use of thermoplastic material which is a mixture of a light coloured silica sand (a bulking agent), a white pigment (titanium oxide to make it look white), a resin binder (to hold it all together), and some glass beads, (to make the lines shine in the dark by reflecting the headlight beam back to the driver).
The property of the night-time visibility of a line is known as its retro-reflectivity, or sometimes "specific luminance". To ensure night-time visibility, glass beads are added to the paint and the still molten thermoplastic line surface, which increases the initial retro-reflectivity of the line. When the line surface becomes worn, the retro-reflectivity of the line will then depend on the glass beads incorporated in the road marking material becoming exposed with wear.
This continuing ability of a line to reflect light to the motorist is enhanced by the quantity and quality of the glass beads in the material as well as the whiteness of the line matrix.
It is worth mentioning that the quality of the workmanship cannot be underestimated in producing road markings of high quality and good durability. In many instances the quality of the glass bead or marking material is falsely accused for poor retro-reflectivity - however, quality road markings are the result of good workmanship (under attentive supervision).