think of it as less or more in terms of protection.common sense should be used here, steel or aluminum. steel has more protection period.dont care where you use the car as one could need the protection on the track or street.
That's not really a true statement. It all depends on how it's designed to fail. The material isn't really relevant on its own.
Modern cars solved the 5mph bumper issue by using plastic fender covers and styrofoam bumper supports. The whole idea, as was mentioned earlier, is to minimize damage from low speed collisions. A 5mph crash should not activate the crumple zones in the unibody or frame. Sure, you wipe out the bumper cover in a small hit, but the important stuff doesn't get bent.
That's what we should strive for.
So what we really actually need is a different kind of lightweight bumper support. The aluminum ones on the market right now are solid tube. Even being aluminum, they'll transmit an impact directly to the mount horns on the frame. What we need is those aluminum supports to have the tubes crimped or sectioned (think a lattice pattern) so they fail in an impact. Sure, the bumper will still hit the fillers, blah blah, but the support should crumple and not transmit the impact to the frame.
If you do hit something at a low speed, sure you're out a bumper, fillers, and new supports. But you don't mess up the mount locations or bend something hard to replace.
They could also be made from plastic, carbon fiber, or fiberglass (I'm looking at you,
@SPOOLFOOL2 ) You're welcome for the idea. No ongoing royalties required. Just send me a set and I'll consider it my licensing fee.