Michigan Gov. Jennifer Granholm has signed into law the state's texting-while-driving ban during a broadcast of "The Oprah Winfrey Show."
Her appearance was aired via satellite from Detroit's Renaissance Center, where Oprah Winfrey thanked her for her leadership.
Granholm's signing is one of many events at "No Phone Zone" rallies in Detroit, Los Angeles, Boston, Atlanta and Washington, D.C., that are part of the broadcast.
Winfrey launched the campaign against distracted driving in January. She has sponsored a pledge on her website asking motorists to commit to not text or talk on phones while driving.
Texting will be a primary offense under Michigan's law, meaning police can pull over motorists solely for usingphones to send text messages.