http://www.pe.com/localnews/inland/stories/PE_News_Local_S_ohvpark17.432e764.html
.....Off-roading demand
Inland counties have the highest percentages of off-highway vehicle registrations in the state, but no state recreation areas for those riders to use.
Top five counties by percentage of off-highway vehicle registrations:
Riverside County
San Bernardino County
San Diego County
Fresno County
Orange County
State off-highway vehicle recreation areas:
Hollister Hills (San Benito County)
Oceano Dunes (San Luis Obispo County)
Prairie City (Sacramento County)
Carnegie (San Joaquin and Alameda counties)
Hungry Valley (Los Angeles and Ventura counties)
Ocotillo Wells (Imperial County)
Sources: Department of Motor Vehicles, Off-Highway Motor Vehicle Recreation Division