Street luge is essentially a fancy term for rolling down a hill on your back at high speeds. It’s not hard to see why injuries (both minor and life threatening) are so common.
Street Lugers can hit incredibly high speeds and are left to deal with a plethora of things that could go wrong: Bad roads, weather issues, faulty equipment, so on and so forth. Speaking of equipment, there isn’t a whole lot there as far as padding goes. A helmet and a body suit can only do so much.