And, by loosening rules, I mean that food trucks are now actually able to serve in SB county outside of the occasional special event.  Here is the relevant quote from the PE article:

On Tuesday, June 5, the San Bernardino County Board of Supervisors unanimously approved rules allowing food trucks to expand their presence, although they will still not be allowed to roam freely as they do in other counties.

Under the guidelines, which go into effect in July, food trucks can operate only at specific locations after getting a permit, but they will be allowed to do so for extended periods. A property-owner could open a food truck lot, for example.