California's 2009 ban on in-vehicle text messaging appears to have influenced driver behavior, according to a series of on-the-street surveys by the Automobile Club of Southern California. Results indicate that in-vehicle text messaging has declined significantly in the seven months after the law went into effect on Jan. 1. The decline indicates that a state texting ban can potentially change driving behavior of motorists, reduce dangerous distracted driving and improve safety, according to the Auto Club.

The Auto Club's study is the first to examine the effects of California's texting law and the only study conducted on a texting ban anywhere in the U.S.

The Auto Club has tracked texting and in-vehicle cell phone use since June 2008 as part of a larger examination of driving distraction. The study was conducted using systematic random samples of a total of 16,500 vehicles passing seven roadside sites in Orange County. Conducted during five time periods -- June, July, and October 2008 (pre-ban) and May and July 2009 (post-ban) -- vehicles were observed at varying times of day (late morning, early afternoon, evening commutes) and on varying roadways (freeway entrances and exits and urban, suburban and small city roadways) to provide an overall look at in-vehicle texting.

Three Auto Club surveys conducted prior to the texting ban taking effect, showed that about 1.4 percent of drivers were texting while driving. The two post-law surveys showed that level had dropped substantially -- to about 0.4 percent -- a decline of about 70 percent overall.

"We're pleased but a bit surprised by the size of the reduction in the texting and driving that we've seen so far," said Steven Bloch, Ph.D., the Auto Club's senior traffic researcher. "The data can seem different from what some people report seeing on the road. But many people forget how high usage levels were. Also, when many people observe higher use, it's for major roads during rush hour. Our surveys are designed to give a broader picture of what drivers are doing in their cars by including many types of roads at different daytime hours."

Texting has become a popular activity. According to the wireless industry trade association CTIA, the number of monthly texting messages reached 110 billion at the end of 2008, up more than 11 times compared to three years earlier. Texting studies also have shown the activity to be far more dangerous than other risky driving behaviors since drivers' hands are off the steering wheel and eyes are off the road.

Through August, the California Highway Patrol issued 1,061 texting tickets statewide. Texting can be difficult to cite since it's a challenge for officers to see motorists inside vehicles with their hands thumb-typing below the dashboard.

"The Auto Club had questions about whether a texting ban could work in California," said Bloch. "No one had studied the effects of a ban before. We knew that it would be difficult for police to cite drivers texting in their vehicles. Although there hasn't been a great number of citations issued, it appears that drivers are getting the message that texting is a dangerous and unsafe activity behind the wheel."

California was the sixth state to ban texting while driving. Many other states are introducing texting bans and federal government officials and legislators are looking into calling for a sharp cut in federal highway funds for states that do not enact bans. The U.S. Transportation Secretary Ray LaHood has stated he supports a text messaging ban nationally and the agency plans to host a distracted driving summit with regulators and stakeholders on Sept. 30 in Washington, D.C.

The Governors Highway Safety Association reversed its earlier position on text messaging laws and now urges states to pass texting bans much like nearly every state has passed for seat belt use and DUI laws.

Despite the publicity surrounding high-profile texting crashes, including last year's Metrolink crash that left 25 people dead and a 2007 car crash that killed five teen-age girls in western New York, research shows that approximately 20 to 25 percent of drivers admit to texting while driving at least once in the past. At the same time, surveys of the general public and AAA's membership support texting laws at 80 to 90 percent.

"As more groups and organizations come out against texting while driving, the crucial issue is: Would such a ban work? Although research is needed to determine the longer term effects of the law, the Auto Club study here in California indicates it can," said Bloch.

Another AAA study showed that distracted driving was top-of-mind for motorists, with 80 percent rating distracted driving as a very serious threat to their safety. Even those who admitted to distracted-driving acknowledged they were putting themselves in danger. For example, more than half of those who admitted to reading or sending text messages or e-mails while driving indicated they were much more likely to have an accident.

A recent Virginia Tech Transportation Institute study showed that the risk of texting sharply exceeds previous estimates based on laboratory research -- and far surpasses the dangers of other driving distractions. That study found drivers who are texting increase the risk of a crash or near-crash by 23 times.