Technology

This will happen with any car. Mass x velocity wins every time. A car would need a giant balloon around it to transfer energy into the pedestrian slowly enough to not injure them significantly.

And what "regular aluminum car"? Cars aren't, by and large, aluminum. They're still mostly steel. Not that it matters, aluminum body panels are less flexible than equivalent steel panels. The places where aluminum is heavily used are things like engines, suspension components, substructures, etc. There are very few cars using aluminum extensively in the body. Ford pickups use it in the bed, Jeeps use it for the engine hood. There are others, but making aluminum body parts is more complex than steel that's easily stamped, and assembly is different.