Ramp Volume Index for Caltrans Districts and associated counties

District 1 = Del Norte; Humboldt; Lake; and Mendocino Counties.

District 2 = Lassen; Shasta; Siskiyou; and Tehama Counties.

District 3 = Butte; Colusa; El Dorado; Glenn; Nevada; Placer; Sacramento; Sutter; Yolo; and Yuba Counties.

District 4 = Alameda, Contra Costa; Marin; Napa; San Francisco: San Mateo; Santa Clara; Solano; and Sonoma Counties.

District 5 = Monterey; San Benito; San Luis Obispo; Santa Barbara; and Santa Cruz Counties.

District 6 = Fresno; Kern; Kings; Madera; and Tulare Counties.

District 7 = Los Angeles and Ventura Counties.

District 8 = Riverside and San Bernardino Counties.

District 9 = Inyo and Mono Counties.

District 10 = Merced; San Joaquin; and Stanislaus Counties.

District 11 = Imperial and San Diego Counties.

District 12 = Orange County.

Those Counties not listed within a Caltrans District above, do not have freeway ramps. They include: Alpine; Amador; Calaveras; Mariposa; Modoc; Plumas; Sierra; Trinity; and Tuolumne.