According to a recent safety study released by the California Office of Traffic Safety, 11 percent of the drivers observed at various times of day at 130 various intersections across 17 counties in the state of California, were practicing cellphone related distracted driving habits. This figure marks an increase of four percent from the results of a similar study conducted in 2011. The demographic that marked the biggest increase in handheld communication use behind the wheel, was drivers 16 to 25 years old. Twice the number of motorists in this age group were observed using cellphones while driving, up from 9 percent in 2011 to 18 percent this year. Safety experts said the rise might be caused by an increase in the number of smart phones in the possession of young drivers. Another safety study conducted by researchers at the University of California, San Diego surveyed 5,000 college students between 18 and 29 years old in San Diego County, and found that approximately 78 percent of respondents reported using a handheld communication device while behind the wheel of a moving automobile. Half of the survey respondents said they engage in text based messaging while driving on the freeway, 60 percent of the respondents reported sending text messages in slow moving traffic, and 87 percent reported sending text messages at traffic signals. Since 2008, using a handheld communication device for any purpose including text and voice based communication while driving has been prohibited by state law in California.