(Pat Wellenbach/Associated Press)

“No call, no text, no update, is worth a human life,” said NTSB Chairman Deborah A.P. Hersman. “It is time for all of us to stand up for safety by turning off electronic devices when driving.”

Is Hersman right? Does banning cellphone use on the roads actually improve safety? Academic research on various cellphone bans suggest its unlikely.

Cellphone bans have gotten a lot of traction lately; the majority of states have some kind of restriction on how drivers use mobile devices. Nine states ban the use of hand-held cell phones while driving and 35 states outlaw texting, according to the National Conference of State Legislatures. Politically, these laws are a pretty easy lift. They restrict a behavior that most drivers intuitively know is dangerous.

But there’s not much in the way of evidence that laws restricting cellphone use actually make our roads safer. Much of the academic research has focused on New York State, which passed the country’s first ban on hand-held cellular devices while driving in 2001. The law has not, according to a 2010 study in Transportation Research, reduced the number of car accidents. And that’s probably because the law didn’t reduce the use of cellphones. The Institute for Highway Safety found, in a separate 2004 study, that cell phone use dropped for about a year after the law passed, but then rebounded to levels similar to before the law was passed.

Other restrictions, like texting bans, turn out to be nearly impossible to enforce. In 2009, I wrote about a Missouri law to ban text messaging, one of 20 texting bans that states weighed that year. The law turned out to be nearly impossible to enforce: In its first year, Missouri netted a mere nine offenders. The reason? For a police officer sitting monitoring cars going by, it’s incredibly difficult to tell the difference between a driver who is texting or making a phone call or maybe just rooting around for some change stuck between the seat cushions.

Distracted driving has long vexed transportation regulators. When car manufacturers began installing radios in vehicles in the 1930s, Massachusetts actually weighed a law that would prohibit listening to the radio while driving. Cellphone bans look like they might have more staying power than radio regulations, but its far from clear they’ll make our roads any safer.