In 2001, New York State became the first state to ban the use of hand-held cellular telephones by drivers. Several other states and cities have followed suit, including New Jersey and Washington DC. Chicago banned hand-held cell phone use last month, as did the Connecticut Legislature earlier this month.

Despite their growing popularity, the effectiveness of these laws is open to question. Publicity and enforcement of the New York State ban produced a drop in the proportion of drivers using cell phones from 2.3 percent to 1.1 percent. But a study published in Injury Prevention found that the rate of cell phone use rebounded to 2.1 percent in 2003 after the initial publicity subsided.

That study focused on several small to medium size upstate communities. The rate of cell phone use by drivers in New York City appears not to have been measured. Nationally, however, a 2004 survey by the National Highway Traffic Safety Administration estimated that eight percent of all motorists were using cell phones at any given time while driving, up from four percent in 2000. Casual observation suggests that New York City drivers at least match the national average. With the continued proliferation of cell phones and increasing functionality of the phones, the number of drivers using phone is likely to continue to grow.

Is cell phone use by drivers a threat to public safety? Published studies have been used to argue both sides of this question. A February 2005 University of Utah study found that young people tested in driving simulators were 18 percent slower in hitting their brakes than drivers who did not use cell phones. Cell phone users suffered from “inattention blindness” – while your eyes may be looking at something, you may fail to see it, or you may fail to see it in time to avoid a collision.

A widely-cited 1997 study published in the New England Journal of Medicine found that the risk of collision when using a cell phone was four times higher than the risk when a cell phone was not being used.

But other studies minimize the actual danger of cell phone use. The University of North Carolina Safety Research office review of State Trooper crash reports (in pdf format) found that cell phones appeared to play a role in only 0.16 percent of crashes. In 2003, Delaware police reviewed 1300 accidents in Delaware and found only four in which motorists were distracted by a cell phone.

Self-reported behavior is notoriously unreliable, however. Accidents are likely to have a number of contributing factors, and what motorist wants to believe that their own actions were key factors?

If government policy is based on the statistical studies of crash risk, then New York State should indeed ban handheld cell phone use by motorists. It should also ban motorists’ hands-free cell phone use, based on University of Utah studies that found that using a hands-free or hand-held phone makes no difference to the level of motorist distraction. About 20 percent of cell phone owners have hands-free devices.

But more than a ban is needed. The history of seat belt laws demonstrates that vigorous public education and enforcement programs are needed to change the public’s behavior. Seat belts have long been proven to be an extremely effective way to reduce injuries from motor vehicle collisions. Yet for years, many people refused to buckle up. But with a extensive educational program and highly publicized enforcement, restraint usage rose dramatically. According to National Highway Traffic Safety Administration (NHTSA) surveys seat belt restraint use increased from 58 percent in 1994 to 80 percent in 2004.

Since the Buckle Up New York Campaign was initiated in May 1999, seat belt use in New York State has risen from 74.2 percent of motorists to 88.3 percent in 2001, though the rate slipped to 85 percent in 2004.

Whether a similar educational and enforcement campaign for the cell phone ban prevents enough injuries to be worth the cost needs further investigation. But there seems to be little question that without such a campaign, laws to ban motorists from using cell phones don’t do much good.

Bruce Schaller is head of Schaller Consulting, which provides research and analysis about transportation, and is also a Visiting Scholar at the Rudin Center for Transportation Policy and Management at New York University.