According to a new study, the bans on the use of hand-held cellular telephones while driving in New York, Connecticut, California and the District of Columbia have had no impact on accident rates.

Researchers from the Insurance Institute for Highway Safety compared the accident data of the two years before and the two years after the ban in each state and found that car crashes had decreased slightly, but that accidents in states with no law banning the use of cell phones declined at the same modest rate, according to AOL Autos.

“Whatever the reason, the key finding is that crashes aren’t going down where hand-held phone use has been banned,” said Adrian Lund, president of the Insurance Institute. “This finding doesn’t augur well for any safety payoff from all the new laws that ban phone use and texting while driving.”

The Institute’s spokeswoman Anne Flemming believes that the lack of any significant change in the number of accidents may be due to the distracting nature of hands-free devices and the deficiency of law enforcement in implementing the ban.

Meanwhile, last week the Department of Transportation prohibited operators of trucks and buses from using handheld devices to send text messages while behind the wheel.