California Code, Vehicle Code - VEH § 21375

(a) The Department of Transportation shall place and maintain, or cause to be placed and maintained, directional signs on freeways indicating the location of the freeway off ramp which may be used to reach a public or private postsecondary education institution having an enrollment of either 1,000 or more full-time students or the equivalent in part-time students, at the request of the institution.  No signs shall be erected pursuant to this subdivision until the department has received donations from private sources covering the costs of erecting the signs.

(b) The Department of Transportation shall place and maintain, or cause to be placed and maintained, freeway directional signs for any institution described in subdivision (a) for which freeway directional signs had previously been erected and which has, on or after January 1, 1980, moved to another location, if that move was done to contribute to the improvement of the institution, as determined by the department.  Freeway directional signs erected pursuant to this subdivision shall be at no cost to the institution.

(c) Subdivision (a) applies to a public or private postsecondary institution which is located within two miles of the freeway in a major metropolitan area, within four miles of the freeway in an urban area, or within five miles of the freeway in a rural area.  Subdivision (b) applies to a public or private postsecondary education institution which has moved to a location which is within the distances specified in this subdivision.