Calling while driving should concern businesses, too, because crashes can cause injuries and raise costs, maybe even opening up employers to liability, Ulczycki said. An NSC survey indicated 45 percent of its member companies have banned the practice for their employees. For 85 percent of them, the policies haven't affected productivity, the group said. Member companies come from a wide range of industries and join the group to take advantage of safety education and training, Ulczycki said.

The mobile phone industry group CTIA disagreed with the NSC's position. It cited situations where cell-phone use could be critical, such as when children need to tell parents they are waiting somewhere to be picked up.

"We believe that safe, sensible and limited use of a cell phone when you're behind the wheel is possible," wrote John Walls, CTIA's vice president of public affairs, in a blog post Monday. "If someone is driving irresponsibly because of cell phone use, they should be cited for that. And under current law, they can be."