Original: Hill Robertson McCarroll (June 30 1867—March 30 1954) was a nurse (later a physician) with the Southern Pacific Railroad in the early twentieth century who is credited by Caltrans with the simple but revolutionary idea of delineating highways with a painted line to separate lanes of traffic.
Simplified: Hill Robertson McCarroll (June 30 1867—March 30 1954) was a nurse (later a physician) with the Southern Pacific Railroad in the early twentieth century.