Drivers using cellular phones are four times as likely to get into a crash that can cause injuries serious enough to send them to the hospital, according to a study being released today.

The study also found that using a hands-free device instead of a handheld phone does not necessarily improve safety.

The report, published in the British Medical Journal, comes on the heels of another study this month that found 90 percent of American drivers admit to at least some unsafe practices while driving. That study found that 43 percent of drivers now talk on the phone sometimes while driving.

The study no doubt will give more impetus to efforts in Hawai'i and elsewhere to restrict cell phone use in cars. More than 23 percent of Hawai'i residents said in a survey last year that they often or always answer cell phone calls while driving.

"I don't think the problem is as bad as on the Mainland, but I still see a lot of people here who aren't paying 100 percent attention," said Andrea Duda, who was visiting Honolulu from Santa Barbara, Calif., last week.

Several bills attempting to limit cell phone use died at the state Legislature this year, in part because many previous studies have been inconclusive on the actual dangers of cell phone use.

Currently, only New York, New Jersey and the District of Columbia prohibit talking on handheld cell phones while driving. In Connecticut, drivers will have to use hands-free devices beginning Oct. 1.

But eight states — Florida, Kentucky, Louisiana, Mississippi, Nevada, New York, Oklahoma and Oregon — prevent local governments from restricting cell phone use in motor vehicles, according to the National Conference of State Legislatures.

The study found an overall fourfold increase in injury crashes in Australia when drivers were using cell phones. Researchers said there were substantially more drivers who were using their phones when they crashed compared with other similar periods of driving.

The Insurance Institute for Highway Safety had tried to conduct the study in the United States but could not get access to records from phone companies. The phone records were available in Western Australia, where handheld phone use has been banned while driving since 2001.

Many previous studies examining cell phone use in vehicles have been based on police reports, but critics say the records are unreliable because it is difficult to corroborate whether a driver was using a phone.