A recent study [PDF] by the Insurance Institute for Highway Safety (IIHS) indicates that while laws in New York, Connecticut, and Washington D.C. have reduced the practice of using hand-held cell phones while driving, the long-term effects have not been uniform.

The nation’s capital saw an immediate drop (41%) in hand-held cell phone use when the ban was instituted 5 years ago, a percentage which remains roughly the same. The reverse appears to be true in New York: In 2001, when the state’s ban took effect, cell-phone use while driving dropped by half. Now, seven years later, hand-held phone use is only a quarter less than what would be expected if no law existed. In Connecticut, cell phone use dropped by seventy-five percent when its law was enacted in 2005. Usage has increased there as well, but by a smaller percentage; now CT drivers use hand-helds sixty-five percent less than if there were no law.

Despite the increases, the IIHS notes that rates of talking on a cell phone while driving (without a hands-free device) is still lower than what would be expected if no laws existed.

For more on the institute’s report, see “Hands-free cell phone laws: Are they effective?” on the Consumer Reports Cars Blog. —Nick K. Mandle