Driver use of hand-held phones already is illegal in 8 U.S. jurisdictions, and these laws are proving successful in reducing proportions of drivers using such phones (see "Cellphones and driving: Do bans improve safety?" Oct. 13, 2009). A new Institute survey also confirms that fewer people are phoning while driving in states with bans, and some have switched to hands-free cellphones. Given the established risk associated with phoning while driving, banning hand-held use would be expected to reduce crashes. But so far it hasn't. Crashes aren't declining. This is the major finding of a new study comparing insurance claims for crash damage in 4 jurisdictions before and after hand-held phone use bans.
Highway Loss Data Institute (HLDI) researchers found steady claim rates before and after the bans. Month-to-month fluctuations in rates of collision claims in jurisdictions with bans didn't change. Nor did the patterns change in comparison with trends in jurisdictions that didn't have such laws.
Specifically, the researchers calculated monthly collision claims per 100 insured vehicle years (a vehicle year is 1 car insured for 1 year, 2 insured for 6 months each, etc.) for vehicles up to 3 years old during the months immediately before and after hand-held phone use was banned while driving in New York (November 2001), the District of Columbia (July 2004), Connecticut (October 2005), and California (July 2008).
The other 4 U.S. jurisdictions where driver use of hand-held phones is banned are New Jersey, Oregon, Utah, and Washington. Data were collected not only in the 4 study jurisdictions but also in nearby jurisdictions without the bans. This method controlled for possible changes in collision claim rates unrelated to the bans — changes in miles driven because of the economy, seasonal changes in driving patterns, etc.
"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," says Adrian Lund, president of both the Insurance Institute for Highway Safety and HLDI.
The HLDI database doesn't identify drivers using cellphones when their crashes occur. However, reductions in observed phone use following bans are so substantial and estimated effects of phone use on crash risk are so large that reductions in aggregate crashes would be expected. In New York HLDI researchers did find a decrease in collision claim frequencies, relative to comparison states, but this decreasing trend began well before the state's ban on hand-held phoning while driving and actually paused briefly when the ban took effect. Trends in the District of Columbia, Connecticut, and California didn't change.
"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 hand-held phones where it's illegal to do so, we would expect to see a decrease in crashes. But we aren't seeing it. Nor do we see collision claim increases before the phone bans took effect."
HLDI researchers compared the District of Columbia's collision claim frequency trend not only with statewide trends in Virginia and Maryland but also with the nearby city of Baltimore's trend. Again, the finding is no difference in the pattern of collision claims. Nor were any differences apparent when HLDI researchers applied a time-based regression model to insurance claims data for each of the study and comparison jurisdictions.
Lund points to factors that might be eroding the effects of hand-held phone bans on crashes. One is that drivers in jurisdictions with such bans may be switching to hands-free phones. In states with all-driver bans on using hand-held cellphones, 22 percent of drivers the Institute surveyed reported using cellphones and always talking hands-free. In this case crashes wouldn't go down because the risk is about the same, regardless of whether a phone is hand-held or hands-free.
No U.S. jurisdiction bans all drivers from using hands-free phones. 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 teen drivers didn't curtail phone use in response to a ban, in part because they didn't think the law was being enforced (see "Despite prohibition, North Carolina teens still use phones while driving," June 9, 2008).