ARLINGTON, Va. — As legislators across the nation enact laws that ban phoning or texting while driving, a new study found no reductions in crashes after hand-held phone bans took effect.

The report by the Highway Loss Data Institute (HLDI) compared insurance claims for crash damage in four U.S. jurisdictions before and after such bans. The researchers found steady claim rates compared with nearby jurisdictions without such bans.

"The laws aren't reducing crashes, even though we know that such laws have reduced hand-held phone use, and several studies have established that phoning while driving increases crash risk," said Adrian Lund, president of the HLDI and the Insurance Institute for Highway Safety (IIHS), of which HLDI is an affiliate.

For example, an IIHS study that relies on driver phone records found a four-fold increase in the risk of injury crashes. A study in Canada found a four-fold increase in the risk of crashes involving property damage. Separate surveys of driver behavior before and after hand-held phone use bans show reductions in the use of such phones while driving.

"So the new findings don't match what we already know about the risk of phoning and texting while driving," Lund points out. "If crash risk increases with phone use and fewer drivers use phones where it's illegal to do so, we would expect to see a decrease in crashes. But we aren't seeing it.”

Lund said that the institutes are currently gather data “to figure out this mismatch.”

There are factors that might be eroding the effects of hand-held phone bans on crashes, Lund said. One is that drivers in jurisdictions with such bans may be switching to hands-free phones, because no U.S. state currently bans all drivers from using such phones. In this case, crashes wouldn't go down because the risk is about the same, regardless of whether the phones are hand-held or hands-free.

Twenty-one states and the District of Columbia do prohibit beginning drivers from using any type of phone, including hands-free, but such laws are difficult to enforce. This was the finding in North Carolina, where teenage drivers didn't curtail phone use in response to a ban, in part because they didn't think the law was being enforced.

"Whatever the reason, the key finding is that crashes aren't going down where hand-held phone use has been banned," Lund said. "This finding doesn't auger well for any safety payoff from all the new laws that ban phone use and texting while driving."

For the HLDI study, researchers calculated monthly collision claim rates during the months immediately before and after hand-held phone use while driving was banned in New York (November 2001), the District of Columbia (July 2004), Connecticut (October 2005) and California (July 2008). Comparable data were collected for nearby jurisdictions without such bans.

To view the full report, click here.