Traffic experts say that when you're distracted, you drive like a zombie, using one-third less of your brain.
More than 200 local law enforcement agencies and 103 CHP offices are participating.
Last Thursday, the California Highway Patrol and Office of Traffic Safety kicked off the "It's Not Worth It!" campaign with a live event featuring "zombie" actors.
Zombies are also being used in public service announcements to drive home the point that you're like a zombie when you text or talk on a handheld phone while driving.
During a similar month-long enforcement effort last year, 52,000 people across the state were ticketed -- four times the monthly average.
The hands-free law has been in effect in California since 2008.
A study from the University of California-Berkeley released last month suggests the law is saving lives.
It looked at crash figures from the two years before the ban went into effect and the two years after.
Researchers found that overall traffic deaths declined by 22 percent, while deaths blamed on drivers using handheld cell phones were cut nearly in half.
Deaths among drivers who use hands-free phones dropped at a similar rate.
So, too, did injuries connected with drivers using cell phones.
Safety advocates say people are getting the message, possibly because of the fines associated with tickets for using cell phones.
The minimum fine for a first-time citation is $159, and it jumps up to at least $279 for a second violation.
Authorities caution that there are still plenty of "zombie" drivers on the road, however.
Last year, about 475,000 drivers statewide were ticketed for the offense.