http://papers.ssrn.com/sol3/papers.c...ract_id=570222
When drivers were conversing on a cell-phone, they were involved in more rear-end collisions, their initial reaction to vehicles braking in front of them was slowed by 8.8%, and the variability in following distance increased by 24.5%, relative to baseline. In addition, compared to baseline it took participants who were talking on the cell phone 14.8% longer to recover the speed that was lost during braking.
By contrast, when participants were legally intoxicated, neither accident rates, nor reaction time to vehicles braking in front of the particpant, nor recovery of lost speed following braking differed significantly from baseline.