(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.