UNITED STATES • Engineers in Las Vegas, Nevada, are testing a new system to illuminate the streets of the city. As if by magic, these solar-powered streetlights can switch themselves on and off when people pass nearby.

The aim of this invention? To reduce both pollution and electricity costs.

Located in the middle of the desert, Las Vegas enjoys high levels of sunshine throughout the year, making the city an ideal place for solar energy use.

A company, EnGoPlanet, recently installed four eco-friendly street lamps on a busy square in the city as part of a project.

The system is simple. A battery is connected to rounded solar panels above the street lights that store the energy needed to illuminate the square. But that is not all.

The battery is also connected to kinetic tiles built into the sidewalk. Whenever a pedestrian walks on the slabs, the kinetic energy produced by the weight of their movement is harnessed.

Thanks to small generators, each step generates four to eight watts, depending on the pressure exerted. The Smart Street Lights are the first to be powered by both the sun and pedestrians' footsteps.

Mr Petar Mirovic, chief executive of EnGoPlanet, said: "Clean and free energy is all around us. Urban cities have to build the smart infrastructures of tomorrow that will be able to harvest all that energy. This project is small, but a very important step in that direction. If it proves to be effective, it will be extended to other major American cities like New York or Los Angeles.

The company is also aiming to raise money on the Indiegogo website in order to provide clean and free electricity to villages in Africa.