Cell yakking drivers more dangerous?

A new study from the AEI-Brookings Joint Center for Regulatory Studies finds:

Once we correct for the endogeneity of usage, our models predict no statistically significant increase in accidents from mobile phone usage, whether hand-held or hands-free. Our results call into question previous cost-benefit analyses of bans on mobile phone usage while driving, which typically assume that such bans will have a salutary effect.