Are Cell Phones Really So Dangerous?

The estimates of annual deaths reported in this week's article (2,600) may well be low. The number, for U.S. deaths related to drivers using cell phones, comes from a 2002 study by the Harvard Center for Risk Analysis (HCRA). Researchers then estimated that the use of cell phones by drivers caused approximately 2,600 deaths.

Because data on cell phone use by motorists are limited, the range of uncertainty is wide, those researchers said. The estimate of fatalities in that HCRA report ranged between 800 and 8,000.

Importantly, the researchers noted (in 2002) that increasing cell phone use could be expected to cause the annual death estimate to rise. The 2002 estimate, for example, was up from an estimate of 1,000 deaths in the year 2000. Logic suggests the number -- though just an estimate -- could be much higher in 2005.

The estimates are based largely on mathematical models, but they are not without basis. In 2001 in California, for example, "at least 4,699 reported accidents were blamed on drivers using cell phones, and those crashes killed 31 people and injured 2,786," according to an analysis by The Los Angeles Times. That number can expected to be low, because of the lack of formal procedures for noting cell phone use as a cause of a traffic accident.

The Times also noted a 1997 study of Canadian drivers "who agreed to have their cell phone records scrutinized found that the risk of an accident was four times greater while a driver was using the phone."

Each year, about 42,000 people die in U.S. auto accidents.

Here is how the new University of Utah simulations were conducted:

Participants in the simulator used dashboard instruments, steering wheel and brake and gas pedals from a Ford Crown Victoria sedan, surrounded by three screens showing freeway scenes and traffic, including a "pace car" that intermittently hit its brakes 32 times as it appeared to drive in front of study participants.

If a participant failed to hit their own brakes, they eventually would rear-end the pace car. Each participant drove four simulated 10-mile freeway trips lasting about 10 minutes each, talking on a cell phone with a research assistant during half the trips and driving without talking the other half. Only hands-free phones were used to eliminate any possible distraction from manipulating a hand-held cell phone.

Thirty times each second, the simulator measured the participants' driving speed, following distance and - if applicable - how long it took them to hit the brakes and how long it took them to regain speed.