The Green Man is also a local legend around these here parts. These here parts being the South Hills of Western Pennsylvania.
The Green Man's Tunnel near the border of two small townships, South Park and Thomas Jefferson. According to my online source, it's off of River Road.* While I have no idea the road name, I've been there, and can navigate there easily.
The "official" legend is that an electrician working in the tunnel was electrocuted (either because he was bad at his job or because lightning struck). He fell into the water under the bridge, and when he haunts, he is either covered in green river slime or glowing green from the electrocution, or both, depending on who's telling the story. In the version of the story I was told, the green man wasn't an electrician but just a local man who was taking a walk through the tunnel, and he wasn't electrocuted, he was knocked into the water by an evil force. His house is supposedly still visible, though overgrown, through the forest. (Told to me when I was in preschool by my best friend who was in elementary school. Of course, I trusted her word! She knew cursive, and multiplication!)
The tunnel itself is not connected to the road, supposedly because of the mystical hauntity things that happen there, but more probably because it's falling down and infested with rodents and other forest life. A second tunnel was built next to the original one, and the second, more modern one is the one that you drive through. It's a one lane bridge with a 90 degree turn in it; if you drive through it, you need to honk your horn before you take the bend to prevent anyone from hitting you. Also, half the inside of the bridge is open-floored, so you can lean over this little brick wall and see the water under the bridge. When I was little, my mom parked the car a few yards down from the bridge and took my brother and I into the tunnel. Sitting on that short wall, looking down at the greenish water, I wasn't much afraid that an "evil force" would come to push me. I was more afraid that a car would come speeding around that bend and smash into the wall, knocking me into the disgustingly slimy water, where the floating vines would pull me down to see the Green Man...
*http://www.route99.org/maps/pennsylvania/allegheny.html