DaytonDailyNews.com

You're driving to work when you remember that morning dentist appointment you forgot to cancel. So you start dialing your cell phone while trying to keep your eyes on the road.

Sorry, but you just increased your chances of having a crash or near-crash by almost three times.

Farther down the road, you decide you can't stand listening to the same five tunes on the radio anymore. So you reach for a music CD when it slips out of your hand and you try to catch it before it falls to the floor.

Whoa! You just upped your chances of a crash or near-crash by nine times.

These are just a few of the findings from the largest, most realistic study to date on how drivers are affected by a growing number of in-car distractions, and the sometimes tragic price motorists pay as a result.

The 100-Car Naturalistic Driving Study tracked for a year the behavior of the drivers of 100 vehicles equipped with five different hidden cameras and a variety of sensors, from proximity radar to GPS locators.

What they discovered is that driver inattention is a bigger problem than anyone had expected. Nearly 80 percent of crashes and 65 percent of near-crashes involved some form of driver inattention within three seconds of the event. Inattention includes not only distractions such as cell phones but drowsiness as well.

The study took place in the Washington, D.C., area in 2006, but researchers at the Virginia Tech Transportation Institute already are planning a national study involving more than 2,500 vehicles. "We will gain a greater understanding of a wider variety of drivers, in more environments, with an improved data acquisition system," said Charlie Klauer, co-principal investigator of the 100-car study.

It's no surprise that researchers have found that the most common distraction for drivers these days is the use of cell phones. More surprising is that the number of crashes and near-crashes attributable to dialing a cell phone is nearly identical to the number associated with talking or listening on the phone. Dialing is more dangerous but takes less time than talking or listening.

Rae Tyson, a spokesman for the National Highway Traffic Safety Administration, said any activity, physical or mental, that draws attention away from driving increases the risk of an accident. That includes tasks as simple as conversing with a passenger or checking the speedometer.

"The biggest deterioration in driving ability we've ever seen was a simulation test in which we asked drivers to start at 842 and start subtracting by 7," Tyson said.

"So what's the deal, you say? You're not manipulating a cell phone. You're not changing a CD. You're not eating or drinking or anything. Both hands on the steering wheel, eyes on the road. But it's amazing what happened to these drivers. To me, that was pretty telling — that people have only so much mental capacity to handle distraction."

Or emotional capacity, for that matter. Take the driver on Interstate 75 who suddenly slammed on her brakes "and came to a complete stop in the middle lane," Richard Plummer of Miamisburg recalled in an e-mail.

Plummer swerved left to avoid the car. As he passed, he could see "the young woman was holding her cell phone up and screaming into it. There were no obstructions on the road. She was just arguing with someone on the phone!"

Young drivers in general are more prone to having accidents while distracted, researchers found. The rate of inattention-related crashes and near-crashes decreased dramatically with age, with the rate for 18- to 20-year-olds four times higher than those age 35 and older.

Researchers say there is no way to calculate the compounded risk of performing multiple tasks while driving, but they do know that drivers who are more willing to engage in "inattention-related activities in general are more often involved in ... near-crashes and crashes," the study found.

Matt Kothensparger of Centerville said he's seen just about every variety of distracted driver on I-675, "but the worst was the lady who was smoking a cigarette, talking on the cell phone and taking her hand off the wheel to take a drink of her Coke. That just stunned me."

Like many readers who responded to our request for examples of distracted drivers, Marilyn Rutledge of Dayton would like to see a ban on cell phone use while driving. "Just tell me where to sign up," she said. "I have had it!"

Ohio has no law against cell phone use or texting while driving, but it gives localities the right to enact their own bans. So far, no jurisdiction in the Dayton area has done so.

Nationally, six states have outlawed driving while talking on a hand-held cell phone — Illinois, Massachusetts, Michigan, New Mexico and Pennsylvania. More than 18 states have enacted cell phone and texting bans for drivers younger than 18 and for school bus drivers. But so far, no state has outlawed the use of hands-free cellular phones, even though the NHTSA said their risk, over time, equals that of hand-held devices.

Tyson is skeptical that laws alone will solve the problem of driver distraction. In the long run, it will take new technology to solve the problems created by the old, he said. Cars of the near-future are likely to be designed with collision warning and aversion systems that help save drivers from their own inattention.

Until then, he said, motorists "must remember that their primary task — job one — is to get down the road safely."