You are speaking about the National Forest portion of Sabino Canyon, which is closed to private vehicles with a shuttle bus available during the day (8 a.m. to 4:30 p.m.)? The shuttle starts at the Coronado National Forest, Santa Catalina Ranger District ranger station right at the National Forest boundary. I'm wondering if there is a county park along Sabino Creek downstream of the Forest boundary. That may be where you see vehicles with "Park Ranger" on the side. I've been there once about 30 years ago, so I don't know the area very well. I can't imagine why an area closed to vehicles would garner so many law enforcement incidents. There is no overnight use allowed on the National Forest portion of the creek.