They seem to be the norm around Pasadena. In the Santa Monica Mountains, there are much harder trails, but with nothing but dirt, weeds, and maybe rocks to catch your fall. Granted, most of this Pasadena trail was rideable for me. I only had to walk 10-20 feet 3 or 4 times, but each time I looked down and laughed at how little thought I would have given to riding it if the penalty for mistakes wasn't so stiff.