This school year, many of the nation's adolescents and teens are sitting in class without the device that can sometimes feel like an added appendage: their smartphones.

States such as Florida, Indiana, Ohio, South Carolina, and Louisiana have passed laws recently to ban or restrict cell phones in K-12 schools, while countless school districts in dozens of other states have implemented policies to limit use.

In Maryland, more than 20 school districts launched programs at the start of the school year to keep phones turned off and out of sight. Baltimore County Public Schools, for instance, introduced a pilot program in 16 middle and high schools that requires students to lock devices in "cell phone pouches" at the start of every class.

Similarly, Howard County high school students must stow phones in backpacks and use them only between classes and during lunch, while elementary and middle school students can't use them at all, unless an administrator makes an exception for a special event or to reward positive behavior.

What's driving the slew of policies?

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