Traffic deaths tied to driving while distracted by activities such as talking on a mobile phone or eating fell 6 percent last year from the previous 12 months, U.S. Transportation Secretary Ray LaHood said.

Crashes linked to drivers being distracted behind the wheel caused 5,474 deaths last year, down from 5,838 a year earlier and accounting for 16 percent of all road fatalities in 2009, unchanged from the previous year, according to the National Highway Traffic Safety Administration.

“These numbers show that distracted driving remains an epidemic in America, and they are just the tip of the iceberg,” LaHood said today in an e-mailed statement.

Researchers think the official statistics underestimate the number of crashes caused by distracted driving, LaHood said in the statement. Police reports in many states don’t document inattention as a cause, he said. Drivers can lose focus by using devices such as mobile phones and portable computers, or such activities as eating, talking and personal grooming.

Drivers in their 20s are the most likely to be involved in a fatal crash tied to distractions, according to the statement. For mobile phones in particular, the 30- to 39-year-old group had the highest involvement.

NHTSA’s statistics show that distracted-driving fatalities as a portion of all deaths increased to 16 percent last year from 10 percent in 2005, the agency said.

The National Safety Council, an Itasca, Illinois-based nonprofit group, found in a January study that 1.4 million crashes a year are caused by drivers using mobile phones and at least 200,000 more by drivers who are texting.

®2010 BLOOMBERG L.P. ALL RIGHTS RESERVED.