During the past 14 years, 2 million pay phones have disappeared from streets in the U.S. Now an idea’s been hatched that would place charging stations for mobile devices and tablets on streets. CEO Petar Mirovic is the CEO of Volta Group, the tech company behind the plan. He says the units operate with a combination of kinetic and solar energy. They are powered by solar panels and the footsteps of people walking nearby. One unit has recently been placed at Webster University in St. Louis, and 100 more are expected to hit the market in the next six months. The company plans to use the same combination of technology to charge streetlights, using tiles embedded in the street to produce energy from passing cars, according to Fastcoexist.com.