According to the National Highway Traffic Safety Administration (NHTSA):

Most drivers know that texting while driving is a
dangerous behavior, but many still use their cell
phones and other mobile devices when they are
behind the wheel, putting themselves and others
at risk. Many drivers see distracted driving* as
risky when other drivers do it, but do not recognize
how their own driving deteriorates.

Almost half (48.6%) of drivers say they answer
incoming phone calls, and 1 of 4 drivers (23.9%)
are willing to place calls on all, most, or some
trips. About half (48.5%) said they never place
calls while driving. Considering there are more
than 210 million licensed drivers in America,1
slightly more than 102 million drivers were
answering calls and 50 million drivers were
placing calls while driving in 2012. At any given
daylight moment across America, there are about
660,000 drivers using cell phones or manipulating
electronic devices while driving.2

* Distracted Driving is any activity that could divert a person’s attention away from the primary task of driving. All distractions endanger driver, passenger, and bystander safety.
1 FHWA. (2011, December). Highway Statistics 2010. Table DL-1C Washington, DC: Federal Highway Administration.
2 Pickrell, T. M., & Ye, T. J. (2011, December). Driver Electronic Device Use in 2010. (Traffic Safety Facts Research Note. Report No. DOT HS 811 517). Washington, DC:
National Highway Traffic Safety Administration.