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Caltrans is doing away with its signature raised white discs on freeways

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They’re called Botts’ Dots

Lots of Botts’ Dots Peter Kaminski | creative commons

Commuters driving on California freeways may notice something missing along the side of the road in the near future. That’s because Caltrans has decided to stop installing the raised white markers that alert drivers when they are drifting out of their lanes, as the Orange County Register reports.

Known as Botts’ Dots, the porcelain discs were named for Caltrans engineer Elbert Dysart Botts, who invented them in the 1950s. Originally, the dots were meant to serve as lane markers, but they became popular for their rumbling effect when driven over—a helpful cue for drowsy or distracted drivers.

But Caltrans spokesperson Vanessa Wiseman tells Curbed the dots are limited by their inability to reflect light. “They’re just big ceramic discs,” she says.

By contrast, the small reflectors already in place along California freeways can be spotted by drivers in low-light conditions—and give cars a similar jolt when run over.

Wiseman says that installing Botts’ Dots was becoming hazardous and disruptive to traffic on busy freeways. As the Register notes, the discs originally lasted up to 10 years, but now must be replaced every six months or so.

Wiseman says that’s because freeways have gotten more use in the days since the Botts’ Dots were first introduced. The automobiles on the road have also gotten larger, with more trucks and other weighty vehicles capable of breaking apart the discs. She says that the rectangular reflective markers are more durable.

New technologies are also helping to phase out the Botts’ Dots. Caltrans now divides lanes with slightly raised thermoplastic striping, which contains tiny glass beads that make the lane lines visible at night.

Meanwhile, grading along the shoulder of the road can provide the jolt drivers need to let them know they are drifting.

Wiseman acknowledges the sentimental attachment many drivers feel toward the Botts’ Dots (the Register interviewed multiple drivers who said the bumpy discs saved their lives in moments when drowsiness caused them to veer out of their lanes).

But she argues that the dots don’t make drivers safer at this point in time, citing a recent multi-year Caltrans study that found no difference in accident rates on roads with and without Botts’ Dots.

Caltrans has already stopped replacing missing or broken Botts’ Dots and will remove them when resurfacing roads going forward.