PP is a great materiel for fairings (especially for off-road bikes, quads & snowmobiles), very crash-resistant & takes paint nicely. Most street bikes use Polycarbonate & ABS, more exotic race kits are fiberglass or even CF.
I think our bumper covers might be PP...I'll have to check that out for sure.
My minivan has some PP side skirts...the passenger side survived a curb strike recently. The nylon clips all paid the price but the skirt survived. A few mounts cracked internally but unbelievably the paint didn't even chip.
Biggest problem with PP and PE (polyethylene) is repair, it typically has to be plastic welded. Most epoxies will not work on PP or PE.