(CNN) -- A study released Tuesday said drivers who use cell phones -- even hands-free models -- are four times as likely to be involved in wrecks involving a serious injury than are drivers who do not use cell phones.
"There was no safety benefit whatsoever from using a hands-free phone," said Anne McCartt, one of the authors of the study, which was published in the British Medical Journal and paid for by the Insurance Institute for Highway Safety.
Researchers for the institute compared information on 456 crashes with driver cell-phone records and interviewed the crash victims shortly after they were treated in hospital emergency rooms.
"Our findings indicate that laws that still allow drivers to use hands-free devices will not eliminate the crash risk of phone use," said McCartt. "In fact, to the extent that drivers perceive that hand-free phone use is safer, in some sense, these laws could have a detrimental effect if drivers increase their use of hands-free phone use."
Connecticut and Chicago are the latest locales to ban cell phone use while driving unless it's hands-free.
In the study, neither gender nor age affected risk.
The study was conducted in Perth, Australia, which bans driving while using cellular phones that are not hands-free.
McCartt said she had wanted to carry out the study in the United States, but phone companies would not release customer billing records, even with a customer's consent.
Still, she said she saw no reason why the findings would not apply equally to drivers in the United States.
The Cellular Telecommunications & Internet Association, a Washington-based trade group, downplayed the findings, saying the distractions associated with mobile phones are no different from those encountered by drivers who eat or talk with passengers as they drive.
"Hands-free is a matter of convenience, a matter of comfort," said John Walls, vice president of communications for the association. He called for education and heightened awareness about any problems to driver safety that might be posed by distractions. "That's the way to change behavior," he said.
The CTIA contends that following these guidelines can minimize risk:
# Assess whether a given call can wait.
# Do not take notes while driving.
# Do not talk while in heavy traffic.
# If possible, pull off the road and park in a safe location to use a mobile phone.
The Insurance Institute for Highway Safety disagrees, maintaining that its study shows that the simple act of talking on a cell phone while at the wheel significantly raises the risk of a serious crash, and following those guidelines will not lower that risk.