About 70 years ago, the alignment of U.S. Highway 395 was designated using old trails and stagecoach routes in Poway. This trail existed from the era of the Mexican land grants and continued into the 20th century. U.S. Highway 395 was completed in 1939, continuing between the Mexican and Canadian borders. From San Diego to Poway, it roughly followed the modern-day path of State Route 163 and Pomerado Road in Poway. In 1949, U.S. 395 was realigned along the current Interstate 15 corridor.
Since U.S. 395 contributed to the establishment of Poway as an inland commercial center, in 2005, the City Council commemorated portions of the historic corridor in Poway by approving the installation of six commemorative "Historic Route" signs along Old Pomerado and Pomerado Roads.