Study Finds Differing Long-Term Effects of Handheld Cell Phone Bans

Phoning while driving and texting behind the wheel are in the news. This is the highway safety issue of the moment, the subject of cartoons and, on a more serious side, the focus of legislation. A key question is whether such laws succeed in changing patterns of driver cell phone use.

Insurance Institute for Highway Safety researchers recently conducted a new round of observations of driver use of handheld phones in three jurisdictions where the practice is banned. The findings, along with results of previous studies, reveal differing effects. In the District of Columbia, the proportion of drivers using handheld phones dropped by about half immediately after a ban took effect in 2004. Nearly five years later, use has edged up a little, but the decline is largely holding relative to nearby Virginia and Maryland.

The story is different in New York, the first U.S. state to prohibit drivers from using handheld phones in 2001. Connecticut enacted a ban in 2005. Comparing trends in these states over time, researchers found immediate effects of both laws. Cell phone use declined an estimated 76 percent in Connecticut and 47 percent in New York. But then use began going back up.

Effects of the laws over time: To quantify the long-term effects, researchers observed phone use multiple times during 2001-09 in both the study states and nearby communities without phone bans. The purpose was to estimate the proportion of drivers expected to be using handheld phones if the laws hadn't been enacted. By this measure, handheld phone use was an estimated 65 percent lower in Connecticut, 24 percent lower in New York, and 43 lower in the District of Columbia than would have been expected without the laws.

In Connecticut and New York, phone use was higher in spring 2009 among women of all ages compared with men and higher among drivers younger than 25 versus 25-59-year-olds. Only 1 percent of drivers 60 and older were observed using phones.

"What's clear from the surveys, despite some variability in their findings, is that bans on handheld phoning while driving can have big and long-term effects, but the safety implications still aren't clear," said Institute president Adrian Lund. "Many drivers still use their handheld phones, even where it's banned, and other drivers simply switch to hands-free phones, which doesn't help because crash risk is about the same, regardless of phone type."

Phone use, texting and crash risk: The question of the risk associated with using various electronic devices while driving was the focus of debate at a recent summit convened by Ray LaHood, U.S. secretary of Transportation. Participants cited a number of studies.

For example, 2006 research from the Virginia Tech Transportation Institute involved instrumenting cars with video and sensors to estimate the risk associated with phoning. The main finding is an almost threefold increase in the odds of crashing or nearly crashing when dialing a handheld phone. The increase is 1.3 for talking. However, this study included only 100 cars and not many crashes occurred during the study period, so the results are inconclusive.

Researchers at the same organization say the risk associated with text messaging may be much higher, based on a new study of truck drivers. The main finding is a 23-fold increase in the odds of crashing, nearly crashing or drifting from a travel lane among truckers who texted while they drove. A limitation is that most of the incidents involved lane drift or other driver error, not crashes, and it's unknown how such incidents relate to actual crashes.

Two studies that rely on the cell phone records of crash-involved drivers show big increases in crash risk when drivers talk on phones, whether hands-free or handheld. The risk of a crash involving injury or property damage is four times as high.

Other studies have been conducted on simulators. Virtually all of these