Younger drivers and females are more likely to use their cell phone while behind the wheel, according to a recent study.

Researchers at the University of Texas found that 18 percent of drivers on academic and medical campuses use their cell phones while driving. Drivers under 25 years old were 4.12 times more likely to use a cell phone while driving compared to older drivers and females were 1.63 times more likely to use a cell phone while driving than male motorists. Unaccompanied drivers were also far more likely to use their cell phones than those who had other people in the car.

"Drivers distracted by cell phones pose a safety threat to pedestrians and motorists in these areas," researcher R. Sue Day said in a statement.

For the study, researchers collected data on a weekday each year from 2011 to 2013 by students enrolled in an epidemiology course on field research methods at each of the School of Public Health's regional campuses. The students observed drivers stopped at randomly selected intersections, recording cell phone use (talking or texting), seat belt use, presence of passengers, and driver and vehicle characteristics.

Cell phone use overall seemed to decrease over the years in Texas, starting at 20.5 percent in 2011 and dropping to 16.4 percent in 2013, according to the study. The 2010 national prevalence estimate for using a cell phone while driving was nearly 9 percent, as reported by the National Highway Traffic Safety Administration.

Drivers talking on the phone while driving decreased by 5.5 percent, but texting while driving increased by 2 percent from 2011 and 2013, according to the study results.

"The data show us that females and younger drivers are most likely to use the phone while driving, which means that public safety campaigns could benefit from targeting those two groups," said Day, who is also a member of the Michael & Susan Dell Center for Healthy Living at the School of Public Health.

The findings are detailed in the journal Preventive Medicine Reports.