Distracted driving – including the use of a cell phone behind the wheel – resulted in 5,474 deaths in the U.S. last year, the Transportation Department announced Monday.

But while those numbers are similar to the stats seen in 2008, Transportation Secretary Ray LaHood warned that the number could be much higher since police in many states do not currently check to see if distraction was a factor in an accident. Drivers most likely to be distracted, meanwhile, are those under 20.

Last year, there were 33,808 people killed in car crashes in the U.S., and 5,474 of them were the result of distracted driving - down slightly from the 5,838 recorded in 2008, according to a report from the National Highway Traffic Safety Administration (NHTSA). Of those killed, 995 involved the use of a cell phone, or 18 percent. Distracted driving also resulted in 448,000 injuries – 24,000 of which involved cell phones, or 20 percent.

Distraction-related fatalities represented 16 percent of overall traffic fatalities in 2009 – the same percentage as in 2008 – but LaHood cautioned in a recent editorial that Monday's numbers are "only the tip of the iceberg because police reports in many states and communities do not routinely document whether distraction was a factor in vehicle crashes."

"Studies show that when a driver looks away from the road to send an e-mail or text message, he or she is concentrating on something other than the road for 4.6 of every six seconds," LaHood continued. "At 55 miles per hour, that is like driving the length of a football field while blindfolded."

Though the percentage did not jump from 2008 to 2009, the proportion of fatalities associated with distracted drivers has increased 10 percent since 2005. Overall, traffic fatalities are also at their lowest levels since 1950.

Broken down by age, drivers under 20 are most likely to be distracted. Of the 3,967 drivers under 20 involved in fatal crashes last year, 619 – or 16 percent – were distracted. Of that 16 percent, 138 of those crashes involved cell phones.

At 24 percent, the 30 to 39 age group had the most incidents of fatal accidents involving a cell phone, but other age groups were not far off. Those ages 20 to 29 were at 21 percent, while those 40 to 59 were at 20 percent.

Monday's stats come one day before LaHood is set to convene the second National Distracted Driving Summit in Washington, D.C. on Tuesday. A webcast of the event will be available at distraction.gov; it begins at 9am.

Also on Monday, AAA released stats that said 52 percent of people feel less safe on the road now than they did five years ago – the leading reason being distracted driving. About 88 percent of those polled said they thought texting and e-mailing while driving was a serious threat, and 80 percent would support a law banning the practice. However, 70 percent of respondents also admitted to talking on the phone while driving and 24 percent said they had texted. AAA did not immediately have data on how many people were involved in the study.