Gov. Tim Walz signed a law Friday requiring motorists to use their cellphones in hands-free mode while driving.

At a signing ceremony Friday, Walz paid tribute to dozens of people surrounding him who lost loved ones in crashes caused by distracted drivers, saying lives will be saved because of their years of campaigning for the law.

"As we stood here listening I couldn't help think and look at the pictures and the stories that were yet to be written and the birthdays and the weddings and the good times and the new jobs," Walz said. "I can't help but think, and for so many of you the dates are on here, I feel the deepest apologies that it took this long."

The law bars motorists from holding and using cellphones or other wireless devices while driving. Built-in systems meet the requirements that systems be voice-activated. So do hands-free mounts sold by many retailers.

The new law marks an important bipartisan success for the Democratic governor and a Legislature divided between a Democratic-controlled House and Republican-controlled Senate, where difficult fights are looming over taxes and spending.