Botts' dots are round non reflective raised pavement marks. These marks are commonly used for road safety and control. In different areas, Botts' dotts are used to mark the lanes in major roads such as highways and arterial roads. They are either white or yellow in color. They serve as substitutes as lines. These are typically made from a combination of different materials, particularly that of ceramic and plastics such as polyester.
These raised pavement marks are credited to Dr. Elbert Dysart Botts who worked at the California Department of Transportation and oversaw research which eventually led to the development of marks for road safety. But despite the Botts' dotts credited to being the result of a research done by the California Department of Transportation, they are used all over the globe such as in Australia, New Zealand and countries in the Middle East like Sudan and Kuwait. In major roads and accident pre areas, streets and lanes are often marked with a combination of Botts' dotts, the non reflective raised marks and the conventional reflective marks. When the combination of the marks is used, it eliminates the need for repainting of lane divider lines. The common areas wherein the combinations of reflective and non reflective raised pavement marks are used include hilly areas where there is frequent fog and rain and areas with a significant amount of snowfall.
Botts' dotts are also common fixtures in areas with high traffic and high accident rates, even if there are no reported snowfalls or for. Ultimately, the use of these increases visibility of lanes and marks at night. This would ensure the safety of the road users can significantly help in decreasing the number of accidents. Pavement marks were thought of early, as early as around the 1930s. The idea was toyed but it was not given much notice because there was no need for it. At the time, additional equipment for traffic control and road safety was not necessary. However, most of the research on these marks at the California Department of Transportation started after the war, around the 1950s. These marks were primarily developed because there was a sudden and exponential increase in the number of cars in the road. As a result of the sudden increase of cars, the number of car accidents increased as well.
The idea of marks then came to the developers primarily because they noticed that there are times that the painted lines were not helpful such as in cases of rain. The early pavement marks were made of glass. Botts suggested in the research that the pavement marks be placed in the roads by use of nails. But this presented a problem to the car owners because in cases where the nails come loose, the nails punctured the tires of the passing vehicles. To solve the problem the team used epoxy to keep the marks glued onto the road. When this proved to be effective, several legislatures mandated that the Botts' dotts be used to help in improving traffic control and road safety. Initially, they were placed in regular roads such as side streets that have two-way traffic. But its effectiveness in assisting the road users made legislators decide that these elevated pavement marks should be placed in highways and major roads as well.
The Botts' dotts were eventually accompanied with reflective marks such as the reflective plastic reflectors to make the lines for lanes more visible.