Yeah that 'No Motorized Vehicles' signage is tricky, George. About a decade ago with the help of the Texas Bike Coalition and our shop, we got some of the local parks people and the state to clarify that this type of sign referred only to engines with displacement, aka gas motors. The rationale was that these signs had been in existence long before there were electric bikes and since ebikes were limited to 20mph (slower than some of the mountain bikers on our city trails) then there was no reason to specifically ban them from park trails. It's still an ongoing battle, though since each municipality can make park laws that are more restrictive than the state or federal laws.