http://www.dot.ca.gov/dist05/paffairs/misc_pr/news_release_various_highways_counties_oh_panel_replacement_5_1_16.pdf
QuoteAn overhead sign panel replacement project along Highways 1, 9, 17, 41, 46, 101, 135, 156 and 183 in Santa Barbara, San Luis Obispo, Monterey, Santa Cruz and San Benito counties begins Sunday night, May 1 ... The district-wide project consists of replacing the existing overhead sign panels with new retroreflective sign panels and turning off the lighting of overhead signs, which will reduce electricity use.