KNOXVILLE (AP) — Four former Tennessee school bus drivers charged with using electronic devices while behind the wheel could face 30-day jail terms if convicted under a new law.

The Knoxville News Sentinel reported on Monday the defendants are charged via recently unsealed grand jury presentments under a new state law. It was passed after the December 2014 deaths of a teacher's aide and two Sunnyview Primary School students, which authorities say were caused by a bus driver who was texting.

The law makes using an electronic device while driving a school bus a misdemeanor punishable by a mandatory 30-day jail term.

Those charged are 68-year-old Robert Eugene Newman, 47-year-old Kellie Rudd, 36-year-old Marvin Lee Hawkins and Margo Flory-Hicks, age unavailable. There are no allegations any students were harmed. It's unclear if any them has an attorney.