No commercial vehicles or trucks shall be permitted to go upon or travel over the driveways and roads located on the grounds of White Rock and Bachman Lakes that are constructed and maintained as part of the facilities of the grounds in their use as a public park. No motor driven vehicle or automobile shall travel at a greater rate of speed than the speed limits posted on standard traffic signs in or upon such driveways maintained in the use of such park grounds. (Ord. Nos. 8018; 32407)