June McCarroll moved to California and was living near Indio in the Coachella Valley of Riverside County, California.

While driving her Ford along a highway near Indio, California, McCarroll was forced off the road by an oncoming army truck. This near-accident sparked her idea to paint a line down the center of highways to separate traffic.

Following her incident, McCarroll began advocating for the implementation of a painted center line on highways. She petitioned local authorities, transportation officials, and civic organizations to adopt her idea, highlighting its potential to improve road safety and reduce accidents.

After years of advocacy by McCarroll, the California Department of Transportation (Caltrans) officially implemented painted center lines on state highways. This marked a significant victory for McCarroll and her vision for safer roads.