Adamant1
Hhhhmm..3 feet seems a little thin for a horse to navigate. I'm no horseman though. I was just looking at the cities website and it says no horses can be owned within city limits. Except in instances of specialized stables. So it would make sense that there would be an ordnance about riding on them public roads to along with it. Especially in a residential area. 
https://www.sanleandro.org/about/municipal_code.asp
The fact that bicycles are restricted from riding along the path to makes me think that it does follow normal street access rules. It would be weird if bikes were restricted but horses weren't. 

I didn't think that First Church of Christ Scientists was actually there, but I kept it because someone had placed it there with a point and I'm trying to be more mindful of not stomping on other peoples work. Plus I didn't feel like taking the time to research it. Thanks for dealing with it though.  