Highway to Cell 

Last year my town made it illegal to use a “hands-on” cell phone while driving'hands-free phones are still OK. Since laws here tend to get passed on the basis of what will look good in the newspapers, I’m wondering: How dangerous is cell-phone use in cars really? You see drivers all the time drinking coffee, putting on makeup, chatting with passengers, etc. As distractions go, the only obvious difference with cell phones is that they’re relatively new and thus a target for legislative busybodies and the easily alarmed'there was all that noise a while back about cell phones causing brain cancer. What’s the Straight Dope, Cecil? For that matter, what’s up with cell phones and cancer?

'Fritz R., Chicago

Wish I could tell you it was all crap, compañero, but uh-uh. Accumulating evidence suggests gabbing on the phone while driving is definitely dangerous'probably more so than other distractions. What’s more, hands-free phones don’t solve the problem. What gets you into trouble, it seems, isn’t so much fumbling with the phone (though that doesn’t help) as the apparent fact that driving and conducting a conversation at the same time consumes more mental processing power than most people can spare. A few data points:

• Cell phones are involved in a lot of crashes. Best evidence: investigations of actual incidents. One study of 456 accidents in Australia requiring a hospital visit (McEvoy et al, BMJ, 2005) found that in 9 percent of cases (40 crashes) the driver had been talking on a cell phone during the 10 minutes prior to the accident, based on phone records. The authors conclude, “A person using a mobile phone when driving is four times more likely to have a crash that will result in hospital attendance.” A 1997 study of 699 accidents in Toronto (Redelmeier and Tibshirani, New England Journal of Medicine) came to a comparable conclusion.

In another study, researchers at the Virginia Tech Transportation Institute installed cameras, sensors and data-recording equipment in 100 cars, then watched what happened over the ensuing 12 to 13 months. They recorded 69 crashes, 761 near crashes and 8,295 lesser close calls. Of driver distractions that may have contributed to these incidents, use of cell phones was by far the most common, occurring in close to 700 cases. The distant runner-up was passenger-related activities, presumably including conversation, with fewer than 400 instances. Of the cell-phone-related distractions, 87 involved dialing a handheld phone and 466 talking or listening.

• Hands-free phones don’t help much. Although laws restricting cell phone use in cars typically make an exception for the hands-free variety, numerous studies show such phones aren’t markedly safer. Dialing does make you take your eyes off the road but, as suggested above, most cell-phone-related accidents seem to happen while the driver is merely conversing.

• Drivers using cell phones have slower reaction times and miss important visual cues. Studies using driving simulators have found that drivers brake slower, fail to see pedestrians and traffic signals, and otherwise pay less attention to the road while on the phone. Some experts compare driving while phoning to driving while drunk, but a study by folks at the University of Utah (Strayer et al, 2004) suggests that in certain respects, drunks actually do better behind the wheel than phone users'they seem to stay closer to the speed limit and brake faster in response to braking vehicles ahead. All in all, there’s solid evidence that talking on the phone is among the more dangerous things you can do while driving.

Other cell-phone risks quickly noted:

• Do cell phones cause cancer? Most studies say no, but some holdouts still argue the point'and they’re not all crackpots, either. One difficulty: Digital phones, the most popular type, have been in common use for less than 10 years, too short a time for long-term health effects to show up.

• Do cell phones cause other bad things? One never knows. A Hungarian study last fall was ominously entitled “Is There a Relationship Between Cell Phone Use and Semen Quality?” (Answer: maybe, and if so, it ain’t good.) I’ve also got a couple reports here of tendinitis and such due to excess sending of text messages.

On the bright side, cell phone interference with medical devices seems to have diminished, due in part to replacement of analog phones by digital ones. Finally, news of a cell-phone-abetted breakthrough in medical diagnosis: UK doctors report that a patient claimed to have “small bumps” in a delicate spot, but by the time he showed up at the clinic the bumps had subsided. “Fortunately, the patient had taken … both a still and a video of his penis” using his cell phone. “The images were very clear and there was no doubt this man had had an outbreak of genital herpes.” Ain’t progress great?

Comments, questions? Take it up with Cecil on the Straight Dope Message Board, www.straightdope.com, or write him at the Chicago Reader, 11 E. Illinois, Chicago 60611. Cecil’s most recent compendium of knowledge, Triumph of the Straight Dope, is available at bookstores everywhere.