There’s a sort of comfort when you change freeway lanes and the tires make a “bump, bump, bump” sound as you cross lane markings.

These raised pavement markers are called “Botts dots,” named for its inventor. Construction crews installed these ceramic tiles (later plastic) on the white freeway lane markers to help drivers know when they were drifting. The bumps also provided tactile feedback when rainstorms made painted lines more difficult to see. For decades Californians joked that the dots allowed them to “drive by braille.”

With such obvious safety advantages, why did Caltrans decide in 2017 not to install any new Botts dots? Two words: Autonomous vehicles.