We’ve seen or heard about drivers on cell phones causing accidents. But new research from the University of Utah also shows that such drivers are also responsible for slowing down traffic flows.

Those talking on cell phones tend to drive more slowly on freeways, pass slowgoing vehicles less frequently and generally take longer to get from one point to another, the researchers found. This can cost society in terms of lost productivity, fuel costs and more, the researchers concluded.

“At the end of the day, the average person’s commute is longer because of that person who is on the cell phone right in front of them,” says University of Utah psychology Professor Dave Strayer, leader of the research team, in a statement. “That SOB on the cell phone is slowing you down and making you late.”

The research, based on a PatrolSim driving simulator, is being presented in Washington, D.C., on Jan. 16 during the Transportation Research Board’s annual meeting.

Strayer’s research group has issued past studies comparing the impairment of cell phone wielding drivers to that of drunk drivers and showing that hands-free cell phones are no less dangerous than handheld ones since it is the conversation that is the distraction.

Much research effort has gone into exploring the various safety and social ramifications of using cell phones in recent years.

Johns Hopkins University researchers earlier this year found that people using cell phones or text messaging in mid-conversation or during an appointment or meeting cracked its Terrible 10 Rude Behaviors List. Cell phone users have even confessed to being a bunch of dangerous, rude liars, according to a Pew Research study .

Carriers, meanwhile, have issued research countering other research about the safety of cell phone transmissions. A four-year long study of cellular telephone base stations out of Japan found their transmissions pose no risk to human health.

And of course, this picture from Russia really emphasizes the dangers of mixing driving and cell phones.

Several states, including California , have also banned driving while holding a cell phone.

Speaking of cell phone dangers, my blogging colleague's latest brush with Mr. Phone-in-his-Ear .