That is a very specific ordinance regarding a very specific trail. I'm sure it's accurate, but when you're scouting new territory, it pays to research carefully.
Here in Los Angeles, I have learned that in some places? The signs are dead wrong, or actually illegal themselves.
There is a place I call "Hell Hill" which is a shortcut into Griffith Park. I have only successfully made it to the top without stopping and walking once, and must have tried well over a dozen times. (Probably never will again!) At the bottom, there are big white and red signs that say, NO TRESPASSING and it also has a sign that says 'No motorized vehicles.'
The No Trespassing signs are illegal. That trail is a public right of way; the senior citizens in the neighborhood clued me in 20 years ago, there is an ancient easement. The sign about motorized vehicles is from the '60s or '70s, predating electric bikes-- and electric bikes are allowed anywhere normal bikes are allowed (except on certain specific trails in some parks, and fortunately, not many around here. I think the crazed electric motorcycle riders are too lazy to find the places I ride, I've only seen mountain bikes and commercial eMTBs.) What I have to pay attention to are the 'No Bicycle' signs, because those are horse trails, and I do not want to have a close encounter with a horse.
There are also a few trails in the hills where there is no signage-- not a lot of people know about them, so they are de-facto mixed use and unregulated. When I ride these, I always dismount every single time I see a pedestrian, smile, wave, and make a friendly comment if they make eye contact. My goal is to convince everyone that eBike riders are rare, superhuman beings who spread joy, good luck and happiness wherever we go and must never be banned anywhere.
I will probably get shot eventually.