1) Background

2) Retroreflectivity

3) How Glass Beads Work

4) Manufacturing Methods

 5) Bead Properties

6) Evaluation of Glass Beads

7) Application of Glass Beads 

8) Evaluation of Glass Bead Application

9) Evaluation of Retrorefl ectivity

10) New Materials



Highway accidents and deaths began with the advent of the wheel. However, man has always been able to solve his problems. In fact, early highway safety methods were truly ingenious. Records show that in Rome, before Christ, recessed bricks or rocks were used in the center of the roads to keep chariots on their own side of the road. Also, over 350 years ago, light-colored rocks imbedded in the center of the roads in Mexico were used for the same purpose. Thus, markings have been used for many years to increase highway safety.


The first striping in the United States is credited to Edward Hines, a road commissioner in Wayne County, Michigan, back in the early 1900’s. In 1921, a black stripe was painted by hand for one block of Madison, Wisconsin, because the Highway Commission concluded that the stripe kept traffi c on the right side of the road. The obvious benefi ts of this centerline stripe were eventually recognized, and the idea spread.


In the early days, a substantial problem was how to get the stripe on the road. One of the first striping machines consisted of a wheelbarrow frame, a five-gallon tank, and a canvas-wrapped wheel with white paint in the tank channeled to drop onto the wheel. This allowed a man pushing the wheelbarrow to paint a white line down the center of the road.


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