It has a “snorkle” like snout, and a long neck that lets it lay on the bottom of a shallow pond or canal and still breath. Waiting for a “meal” to swim by. You can get an idea of the size of it’s mouth in this photo. I read a large one could bite off a finger or maybe even a hand. They have very long necks, so picking up a large one might not be a good idea, even to get it out of the road.
I think this might be a female since males are smaller and only get a bit over a ft long. This one was longer than that. She looks at me as if to ask if I am done yet and can she get on with her business.
Then headed back into the ditch, and on her way.