There may be city police departments ins CA that have varying policies. But I can assure you you will not find that on CHP's web site and it will not hold up in court. Having completed traffic school a number of times over the years I am practically college educated on the subject.

Here's from the CA DMV drivers manual.

http://www.dmv.ca.gov/pubs/hdbk/spee...tm#speedlimits

"California has a "Basic Speed Law." This law means that you may never drive faster than is safe for current conditions. For example, if you are driving 45 mph in a 55 mph speed zone during a dense fog, you could be cited for driving "too fast for conditions." You may never legally drive faster than the posted speed limit, even if you think it is safe."

Actual Vehicle code is here.
http://www.leginfo.ca.gov/cgi-bin/wa...ction=retrieve

Anecdotally, I'm personally seeing WAY more people getting pulled over by CHP lately. California is still a walk in the park compared to some other states with speed traps around every corner but CHP is definitely stepping up enforcement concurrent with the States ongoing budget crisis (which I am sure is just a coincidence)