We all know someone who's fused to their cell phone, texting, talking, twittering and incessantly updating their calendars - even when behind the wheel. The problem is rampant among teens, and a new study confirms the obvious: it's dangerous to text behind the wheel.

It's equally dangerous to use an MP3 player. Both texting and using MP3 players caused increased rates of speed changes - typically slowing down - and 'lane position deviation'. The study, performed by Eastern Virginia Medical School, was presented to the Pediatric Academic Societies this past weekend.

The study is an informed look at a problem that is just now coming to the attention of legislators around the country. New laws to restrict the activity are being contemplated in many states, and for good reason. Of the 21 subjects in the study, all were between 16 and 18 years of age, and all had at least six months driving experience. All subjects were also screened for attention disorders or unsafe driving histories, so that only the attentive, safer drivers remained.

The result: several of the students struck and killed 'virtual' pedestrians in the computerized simulation. "What this study demonstrates is that not only does your speed go up and down, you're swinging wide left and right," said Donald Lewis, M.D., vice president of academic affairs at CHKD and chairman of the EVMS Department of Pediatrics. And when texting, "You're a hazardous driver, to yourself and everybody else."

This study backs up another performed last September which showed texting while driving was more dangerous than being under the influence of either alcohol or cannabis.

If you're a parent or just keen on self-regulating, you can take matters into your own hands, however. A service from DriveAssist keeps drivers from texting or talking behind the wheel by detecting the phone's movement and locking out certain features. For more on that technology, check out our original story here.