"This study is highly significant for California," said OTS Director Christopher J. Murphy. "It gives us a base to measure against in years to come as we combat this serious threat to safety on our roadways."

A federal study in 2009 showed that about 9 percent of drivers nationwide were talking on cellular telephones or texting while driving.

The state's study -- billed as the first-ever observational study and done in March -- showed that 9.8 percent of Southern Californians are yakking or texting.

In suburban area, the numbers were typically higher, and about 12 percent of Central Californians were observed talking or testing.

In Northern California, the figure was 6.9 percent.

The study included 130 intersections in 17 counties, where observers took notes on 5,413 drivers holding phones to their ears, wearing a Bluetooth or headset device or those who were texting.

In the first half of April, dubbed Distracted Driving Awareness Month, at least 20,455 drivers were ticketed for holding phones to their ears while driving or texting. Fines range from $159 for a first offense and rise to $279 for repeat offenses.

"This shows how ingrained the use of mobile devices has become. Even faced with laws, studies and stories of tragedy, too many are not able to put down their cell phones," California Highway Patrol Commissioner Joe Farrow said.