Public safety officials and driving instructors may be hailing a new law banning cell phone use by young drivers as a lifesaver, but without quantifying how the new law reduced accidents, this is hollow praise. Legislators who passed the law in June should want to know if the ban makes a difference so they can better determine if further distracted driving rules are needed or if this law should be of short duration.

A law prohibiting anyone under the age of 18 from using a cell phone while driving went into effect last week. The ban covers all handheld electronic devices and institutes a $50 fine for a first violation and $250 for a second offense.

Carl Hallman of the Maine Bureau of Highway Safety praised the new law, saying it will encourage young drivers to pay attention to the road, not their electronic devices. But he wondered how the law would be enforced and how its impacts would be tracked.

Public Safety Department spokesman Stephen McCausland said the law isn’t about writing tickets but getting the message out to teens and parents about the dangers of distracted driving. Public safety officials and lawmakers should want to know if this message is heard, however. One crude way to do this is to compare teen accident rates before and after the law change. Another is to track violations and see if they decrease in a couple years.

The State Police are updating the crash reports used by the state’s law enforcement agencies to include more detailed information on what distractions contributed to accidents. While largely self reported, this information can help determine if this law is effective.

Current national data is mixed, according to the Insurance Information Institute, an industry group.

Driver inattention of one form or another was involved in almost 80 percent of crashes and 65 percent of near crashes within three seconds of the event, according to a study released last year by the Virginia Tech Transportation Institute and the National Highway Traffic Safety Administration.

The most common reason drivers were distracted was the use of cell phones, followed by drowsiness, according to the study. Despite this, cell phone use was the cause of fewer crashes or near misses than other distractions. Reaching for a moving object such as a falling cup increased the risk of a crash or near crash by nine times, while talking or listening on a handheld cell phone increased the risk by only 1.3 times, the study found.

A study by researchers at the University of Utah published last year concluded that talking on a cell phone, even a hands-free model, while driving was as dangerous as drunken driving. In an earlier study, researchers at the university found that motorists who talked on hands-free cell phones were 18 percent slower in braking and took 17 percent longer to regain the speed they lost when they braked.

With a targeted ban in place, lawmakers have an opportunity to see if it helps. The information they gather will enable them to make better decisions about this problem in the future.