When the state's hands-free cellphone law was enacted three years ago, the rules seemed so simple. Holding a phone in your hand to make a call would be illegal. Few ifs, buts or maybes.

Then came a law against texting. Then came an explosion of phones that double as GPS devices, cameras, music players, voice recorders and email dispensers. And today, amid an unprecedented crackdown this month on cellphone scofflaws, what's legal and what's not has motorists and even some cops scratching their heads.

"When you look for loopholes, the whole issue of cellphone use, texting or distracted driving becomes confusing, if not overwhelming," said Officer Steve Creel of the California Highway Patrol.

For example, it's legal to read, select and enter a phone number while driving -- as long as you put the phone down before talking. But you can't send a text while sitting at a red light.

Some officers say it's OK to play some music from your phone if it's done quickly. But most -- though not all -- say using the phone's GPS function is not legal if the phone is held in the hand.

"The GPS thing is goofy," said Phil Fernandez, 50, of Palo Alto, the CEO of a San Mateo software company. "Why can I use the GPS that's built into my dashboard, or a dedicated portable GPS device, but not Google Maps on my iPhone? These laws should be clarified and made consistent."

San Jose State professor John Clapp uses his cellphone to record memos that he can later transcribe as he commutes from Menlo Park. That's illegal, police say. But using a separate tape recorder would be perfectly legal under the hands-free law.

"If my voice memos make me a criminal, then I think it must be a poorly written law," Clapp said. "I think we should be able to do better."

Software engineer Paul Brown of Fremont is so baffled by what's OK that he is considering tossing his phone in the trunk to avoid risking a ticket. Fines and fees now run to $159 and would increase to more than $300 under proposed legislation.

"Better to just not tempt fate at all," Brown said.

The hands-free law prohibits a driver from using a cellphone unless that phone "is specifically designed and configured to allow hands-free listening and talking, and is used in that manner while driving."

Translation: Use a speakerphone (as long as it's hands-free) or an earpiece to avoid a ticket.

Before the hands-free legislation was enacted, laws against traveling at an unsafe speed were used to combat distracted drivers who may have been eating a sloppy cheeseburger, fiddling with a CD or even yelling at kids in the back seat. Today those laws can still be used to cover loopholes in the cellphone law.

If scrolling through your iPod while driving is causing you to veer out of your lane, "then the safe speed for doing that is zero," said CHP Officer Dave Barnett. "So the officer would cite you."

Yet punching in a phone number to make a call -- which takes more concentration than a brief phone conversation -- is legal.

"Go figure," Barnett said.

There is no legislation in the works that would make hands-free laws any clearer, although a bill by state Sen. Joe Simitian, D-Palo Alto, would increase fines and make a second offense a moving violation.

"As technology changes, so should the law," said Simitian, who wrote the hands-free and texting laws enacted in 2008 and 2009. "But whenever we can, we want to legislate generically to avoid the need for constant and confusing changes."

Evolving technology may offer some help. Sprint and T-Mobile announced last week that they now offer apps that would identify when a car is moving more than 10 mph and lock the phone to prevent users from making calls or sending texts, except for 911 calls. It is aimed at parents concerned about their drivers younger than 18 -- who, under the law, are not allowed to use a cellphone while driving at all, hands-free device or no.

Police say the search for loopholes detracts from the safety issues in play. Talking to someone while driving, dialing a number, texting or scrolling through email are all distractions to be avoided.

But when a call comes in, the temptation to pick up the phone is so great. Clayton Young of San Jose says he recently managed to keep both hands on the wheel while talking on the phone -- which was being held up to his ear by his wife.

"I'm not sure if I broke the law," he said. "If the CHP stopped me, would I receive a ticket?"

Yes, said CHP Officer Brandie Dressel. No, said Lt. Chris Monahan of the San Jose Police Department's traffic unit.

"Your hands are free and it's not illegal," Monahan said. But, he continued, "It's not always the hands that are the problem, sometimes it's the mind that isn't focused. If people want to talk on the phone, including me, pull over. It's just safer."