Until recently, I did not wear a helmet when on a MUP, only when i will be in the street. I avoid riding in the street but sometimes I do in order to get from one place to another like the Hudson MUP to Central Park. Last week I was on a MUP when I noticed a gentleman riding a very bright red Cannondale. I guess it was the color which caught my attention. Anyway, he was on the part of the MUP which circled a rather large pond. As he neared me, he began to turn to his left( I would say he was at about 15-20mph) when his rear wheel slipped, he went into yaw and then crashed. I watched as he went down and his head bounced off the asphalt. He and the bike slid a few feet and then came to a stop, as did I in order to render aid if needed. His helmet (yes he was wearing one) was badly damaged. The plastic shell had cracked into a few peices and was scattered about. He had some roadrash on his elbow, hip and had his wits about him. We noticed that there were a few wet leaves on the road where he fell and it appeared what was why his tire slid out. I had some stuff to clean off his roadrash ( I keep a few things handy in my bag) and he went on his way. I can tell you his head hit the ground hard. I cannot fathom the injury to his head had he not been wearing a helmet.
I should have known better and always worn a helmet. Lesson learned, I will from now on.