Industry study: crash risk while using cell phone is four times higher.

The Insurance Institute for Highway Safety has found using a cell phone while driving increases the risk of injury-causing crashes by four times. Hands-free phones are just as risky as hand-held cell phones, the study found.

"This isn't intuitive. You'd think using a hands-free phone would be less distracting, so it wouldn't increase crash risk as much as using a handheld phone," Anne McCartt, IIHS vice president and one of the authors of the study, said in a statement. "But we found that either phone type increased the risk. " McCartt said this may be because most "hands-free" phones in use today aren't completely hands-free, but she said there was insufficient data to compare different types of hands-free phones, such as voice-activated phones.

The study was conducted in the Western Australian city of Perth, where cell phone records could be obtained and drivers in crashes were highly cooperative. The IIHS said it wanted to conduct the study in the United States, but cell phone companies were unwilling to make customer billing records available, even with permission from the customers, for use in the study. Phone records were used to compare phone use 10 minutes before an actual crash occurred with use by the same driver during the prior week, the IIHS said.

Subjects of the study were 500 drivers treated in hospital emergency rooms for crash injuries from April 2002 to July 2004.

"The main finding of a fourfold increase in injury crash risk was consistent across groups of drivers," McCartt said. Male and female, young and old, all had the same increase in risk when using a cell phone, the study found.

The study also found:

* 75% of the cell phone-related crashes took place in clear weather conditions;

* 89% involved other vehicles; and

* More than half of the injured drivers said the crash occurred within 10 minutes of the start of their trip.

The IIHS said this study's findings are consistent with a 1997 Canadian study that also found a fourfold increase in crash risk from use of cell phones.