Behavioral science professor Saurabh Bhargava’s research has a new take on an old tale: Talking on cell phones while driving might not actually be that dangerous.

A four-year study published last month by Bhargava of the Booth School of Business’s National Opinion Research Center and Vikram Pathania of the London School of Economics finds no positive correlation between the rise in cell phone use and the rate of car crashes, despite their initial hypothesis.

The group expected a rise in crash rates to correlate with the increase in cell phone use at 9 p.m., when many phone plans shifted to free calls, but they found no correlation.

The findings point to a possible “mechanism that mediates the link between cell phone use and crashes,” according to Bhargava, which he believes could be driver compensation.

“Other researchers have estimated the economic value of cellphone usage while driving to be on the order of several billion dollars,” Bhargava said. “So this really begs the question—given the implicit costs of such bans, what are the policies that would genuinely address the dangers posed by cell phones?”

The pair argues that blanket bans on cell phone use, like those in place in eight states and the District of Columbia, are costly and ineffective, based on their findings.

“Depending on the underlying mechanism at play we might think about partial bans on cellphone use or banning cellphones as a secondary offense,” Bhargava said. Both researchers believe the nature of the mechanism requires further research, which might influence the way policy-makers approach cellphone bans.

Still, Bhargava and Pathania caution against using the study as evidence that driving while talking on a cell phone is not at all dangerous. They speculate that drivers who are aware of the added risks might only be driving more carefully.