Pedestrians, beware: As more drones take to the sky, it's only natural to wonder what's going to happen if some of those drones inevitably come crashing down. Fortunately, some researchers are already working on that particular problem.

A team at MIT's Computer Science and Artificial Intelligence lab have found a way to 3-D print materials that could lessen the impact created by a crashing robot. They invented "programmable" rubber materials that, if used to make drones, could cause less severe impact on anything they ram into--people included.

The researchers create the viscoelastic material by programming via a computer the exact levels of stiffness and elasticity needed in each part of the printed product. Solids like rubber and plastic are combined with non-curing liquids to produce a component with the precise firmness and springiness required. The part is printed in layers, so different areas can have different properties, thus making its behavior upon impact more controllable.

As explained in a research paper by the team, until now, manufacturers have generally been limited to using mass-produced materials when building drones. Giving manufacturers the ability to create safe, shock-absorbing components themselves would mean they'd also have the ability to print and test materials--which could lead to safer products.

Drone regulations in the U.S. have proven strict, which is why Amazon recently took its drone delivery test program overseas to England. Many of the FAA's rules have revolved around safety, and with good reason: What happens when a several-pound drone inevitably malfunctions and falls out of the sky? What about when it accidentally flies into a person?

MIT's invention could potentially help solve that. Components that can be programmed throughout could give manufacturers the freedom to inexpensively create, say, high-tech customized bumpers, or safer, rubbery propellers.

The material has another purpose: protecting the expensive hardware. A video released by MIT's lab on Monday shows two cubes being dropped onto their corners. The standard rubber one bounces wildly; the 3-D printed one, thanks to a metallic spring and its viscoelastic material, bounces once and lands safely on its side. Being able to control what happens upon impact could not only limit the damage caused by a falling drone but also prevent it from smashing to smithereens.

Beyond drones, there are other possible use cases for the materials, like athletic equipment. There's a fortune to be made by whatever company can create a safer football helmet that gets the stamp of approval from players and leagues. Some companies, like Seattle-based startup Vicis, are creating helmets with rubbery surfaces, which could help lessen the possibility of head injuries. The helmets currently run $1,500 a pop, though, so it's possible that in-house 3-D printing could make that more accessible.

Check out MIT's video below to see the 3-D printed materials in action.