Botts' dots

Botts' dots (turtles in Washington and Oregon or buttons in Texas and other southern states) are round non-reflective ceramic[1] raised pavement markers.

A "former student of Botts named Herb Rooney developed a tough, fast-setting epoxy that could bond the raised reflectors to virtually any solid surface".

In 2017, Caltrans announced that it would stop using Botts' dots as the sole indicator of lane division, due to cost and worker safety, and in order to make roadways more compatible with self-driving cars.

More recently, Botts' dots have been used in the snow-free areas of Alabama, Florida, Louisiana, Mississippi, Nevada, Georgia, Washington, and Texas.

Some states that do experience snow, particularly Pennsylvania and Massachusetts, use Botts' dots only during the summer months for temporary lane markings in construction zones.

Until the late 1990s, Botts' dots were also used extensively in the snow-free areas of Arizona; however, ADOT has since ended this practice, opting for painted stripes with reflective markers instead.

These pavement markers are usually augmented with reflective paint and delineators placed on plastic or metal posts at regular intervals along the edges of the road.