Despite a significant increase in the total number of miles driven by American motorists, highway deaths last year were at their lowest level since 1949, according to data released by the U.S. Department of Transportation (DOT).

Transportation Secretary Ray LaHood attributed the decline to the efforts of safety agencies and partner organizations.

There were 32,885 traffic fatalities in 2010, even as drivers traveled nearly 46 billion more miles during the year -- an increase of 1.6% over the 2009 level.

The updated information released by the DOT's National Highway Traffic Safety Administration (NHTSA) indicates that 2010 also saw the lowest fatality rate ever recorded, with 1.10 deaths per 100 million vehicle miles traveled in 2010, down from 1.15 deaths per 100 million vehicle miles traveled in 2009. Other key statistics include:

■ Fatalities declined in most categories in 2010, including for occupants of passenger cars and light trucks (including SUVs, minivans and pickups).
■ Deaths in crashes involving drunk drivers dropped 4.9 percent in 2010, taking 10,228 lives compared to 10,759 in 2009.
■ Fatalities rose among pedestrians, motorcycle riders, and large truck occupants. New Measure of Fatalities Related to Distracted Driving

NHTSA also unveiled a new measure of fatalities called "distraction-affected crashes." Introduced for 2010 as part of a broader effort by the agency to refine its data collection to get better information about the role of distraction in crashes, the new measure is designed to focus more narrowly on crashes in which a driver was most likely to have been distracted. While NHTSA's Fatality Analysis Reporting System (FARS) previously recorded a broad range of potential distractions, such as careless driving and cell phone present in the vehicle, the new measure focuses on distractions that are most likely to affect crash involvement, such as distraction by dialing a cellular phone or texting and distraction by an outside person/event. New data released today by NHTSA using its refined methodology show an estimated 3,092 fatalities in distraction-affected crashes in 2010.

The NHTSA effort to refine distraction data is similar to a step taken with alcohol information in FARS data for 2006. Prior to 2006, FARS reported "alcohol-related crashes," which was defined as crashes in which a driver, pedestrian, or bicyclist had a blood alcohol level of .01 or higher. In an effort to focus on crashes in which alcohol was most likely to be a causative factor, NHTSA introduced the new measure, "alcohol-impaired driving crashes," with a more narrow definition including only those crashes in which a driver or motorcycle rider had a blood alcohol level of .08 or above, the legal limit in every state.

While the explicit change in methodology means the new measure cannot be compared to the 5,474 "distraction-related" fatalities reported in 2009, other NHTSA data offer some indication that driver distraction continues to be a significant problem. The agency's nationwide observational survey of drivers in traffic remains unchanged between 2009 and 2010, with 5 percent of drivers seen talking on handheld phones. In addition, given ongoing challenges in capturing the scope of the problem — including individuals' reluctance to admit behavior, lack of witnesses, and in some cases the death of the driver — NHTSA believes the actual number of crashes that involve distracted driving could be higher.