Even after the implementation of center lines in California, McCarroll continued to advocate for their adoption nationwide. She promoted the benefits of her idea and worked to raise awareness about road safety.

While Caltrans credits June McCarroll with the original idea for highway centerlines, the Federal Highway Administration and Michigan Department of Transportation contest this claim, pointing to earlier instances of painted centerlines in Michigan. Despite this dispute, McCarroll remains a notable figure in the history of road safety.

June A. McCarroll passed away on March 30, 1954. She leaves behind a lasting legacy as a pioneer in road safety, even with the ongoing debate surrounding the originality of her idea.

Despite the contested nature of her claim to inventing the painted centerline, McCarroll's story continues to be told. She is remembered for her contribution to road safety advocacy.