Delta 6
There is a gate immediately after the parking lot. Presumably it only allows private access to cars and public access to foot/bicycle/equestrian traffic (I edited it to indicate as much). From the map (https://www.ebparks.org/images/Parks/PtPinole/Point-Pinole-map-2250w-20180726.gif) it is a little ambiguous as to whether the bridge itself is considered a road or a paved path.