Pavement markings are a vital safety feature on most county maintained roads. Not only do they mark the center of the road and designate passing and no passing zones, they can also delineate the edge of the road, warn of railroad crossings, show where you should stop at a stop sign or traffic signal, create cross walks, and designate special lanes (bicycle and turn lanes).
Maintaining these markings is quite expensive at over $200,000 per year to paint approximately 365 miles of road. Over 8,000 gallons of yellow paint and 9,000 gallons of white paint are applied annually. Nearly $10,000 of this program went into durable marking work (preformed thermoplastic markings) which are used for stop bars, advance railroad crossing markings, crosswalks, turn arrows, "ONLY"s and other words, as well as channelizing lines.
Roads are repainted as the stripes get worn by traffic. Most roads require striping yearly while some require striping twice a year. The striping program also stripes the roads involved in the Road and Bridge Department's chip seal program. Roads with a fresh chip seal surface usually require two paint applications on the road centerline.
All pavement markings are retroreflective, meaning they reflect light from headlights back toward the driver. This retroreflectivity is accomplished through the introduction of glass beads into the wet paint. When the paint dries, the beads are trapped throughout the thickness of the paint. As the paint line wears the beads on the surface wear off, while new beads are being uncovered.
Several factors effect the durability of painted pavement markings. Some of these are the traffic volume, the number and severity of snow storms (sanding of the roads wears the markings faster), curves in the road (traffic tends to cut the corner slightly), age of the pavement (newer pavements absorb more paint leaving less on the surface where it is needed), and paint formulation.