2005 California Vehicle Code Sections 38305-38310 Article 3. Speed Laws

38305.  No person shall drive an off-highway motor vehicle at a
speed greater than is reasonable or prudent and in no event at a
speed which endangers the safety of other persons or property.
38310.  The prima facie speed limit within 50 feet of any
campground, campsite, or concentration of people or animals shall be
15 miles per hour unless changed as authorized by this code and, if
so changed, only when signs have been erected giving notice thereof.