A new insurance industry study has found that state laws banning the use of handheld devices to make calls or send text messages while driving haven’t resulted in fewer vehicle crashes.

The study, released Friday by the Highway Loss Data Institute, examined insurance claims from crashes before and after such bans took effect in California, New York, Connecticut and Washington, D.C.

The organization found that claims rates didn’t go down after the laws were enacted. It also found, no change in patterns compared with nearby states without such bans.

Six states and the District of Columbia ban talking on a handheld device for all drivers, while 19 states and the District of Columbia ban texting while driving, according to the Governors Highway Safety Association.

The Highway Loss Data Institute, an affiliate of the Insurance Institute for Highway Safety, said its findings “don’t match what we already know about the risk of phoning and texting while driving” and said it is gathering data to “figure out this mismatch.”

It said one explanation could be an increase in the use of handsfree devices, in places with bans on handset use while driving.

Past research by, the insurance institute and others had shown drivers were four times more likely to be in a crash while using cell phones.

Jonathan Adkins, a spokesman for the governors association, said the study “raises as many questions as it answers.” The group is concerned that bans on handheld devices simply encourage more drivers to use handsfree devices, which, it says, are just as risky.

The governors association is urging states to pass texting bans, but hold off on banning other cell phone use while driving until there is more data. The National Safety Council, meanwhile, Supports a total ban on cell phone use while driving, including the use of hands free devices.

In Austin, it became illegal on January 1 for drivers to use a cell phone for texting or any other purpose except making a phone call.