Washington (CNN) -- Your eyes aren't deceiving you.
A federal study says one in 20 drivers observed at any given moment is holding a mobile phone to his or her ear, and that almost one in 100 can be observed sending a text message or otherwise manipulating a digital device.
At the typical daylight moment, some 13.5 million drivers are on a hand-held phone nationwide, the study says.
The National Highway Traffic Safety Administration released the study Thursday, saying the use of phones while driving is holding steady, and text messaging is growing, despite laws limiting hand-held devices and a tidal wave of publicity about tragedies cause by distracted drivers.
NHTSA said there's evidence that 3,092 deaths -- one-tenth of all roadway fatalities last year -- involved distracted drivers, although they believe the actual number may be far higher. Determining the cause of distracted driving fatalities is difficult, authorities said, because there frequently are not witnesses, and the distracted driver may be dead.
Accordingly, officials Thursday also unveiled a new measurement of fatalities which -- to be called "distraction-affected crashes" -- that they say will help them follow trends and focus research in the future.
The old method, used to estimate 2009 distracted driving deaths, included a broader range of indicators, including cases of "careless driving," and cases in which a mobile phone was found in a car, even if there was no evidence it was being used.
But the new methodology focuses more narrowly "on crashes in which a driver was most likely to have been distracted," NHTSA said.
The number of fatalities dropped from 5,474 people in 2009, to 3,092 people in 2010, but NHTSA said the two numbers should not be compared, because of the changing methodology.
NHTSA Administrator David Strickland said in a statement the new methodology is intended to improve the agency's understanding of the problem, to lay the groundwork for additional research.
Indeed, there is some evidence the problem is holding steady, if not worsening, officials said.
Under the so-called NOPUS study -- National Occupant Protection Use Survey -- trained observers at randomly selected sites track the extent to which they see people use cell phones and other electronic devices while driving. Data is collected only during daylight hours, and the observers look only at stopped vehicles.
The study said the percentage of drivers who use hand-held cell phones stood at 5 percent in 2010, while the percentage of drivers who were text-messaging or visibly manipulating hand-held devices increased significantly from 0.6 percent in 2009 to 0.9 percent in 2010.
According to NHTSA, as of May 2011, eight states (California, Connecticut, Delaware, Maryland, New Jersey, New York, Oregon and Washington) as well as the District of Columbia and the Virgin Islands ban driving while talking on a hand-held cell phone. Thirty-two states, the District of Columbia and Guam ban text messaging for all drivers.
Some states, such as Maine, New Hampshire and Utah, treat cell phone use and texting as part of a larger distracted driving issue. In Utah, for instance, cell phone use is an offense only if a driver is also committing some other moving violation, other than speeding, NHTSA said.