No hedge, shrub or other vegetation, fence or similar structure, shall be maintained across any existing walkway in a sidewalk area or shoulder. The intent of this restriction is to keep free a walkway for pedestrian or other lawful public travel without interference by or with vehicular travel. No encroachment of any nature will be permitted or maintained which impedes, obstructs or denies such pedestrian or other lawful travel within the limits of the right-of-way or which impairs sight distance for safe pedestrian or vehicular traffic. (Ord. No. 1201, § 2 (part).)