Access to and from a PBD shall be controlled in the interest of public safety. Each separate use, grouping of attached buildings or groupings of uses permitted as part of a single integrated PBD shall have not more than two accessways to the road on which it is located. Insofar as practicable, the use of common accessways by two or more permitted uses shall be provided in order to reduce the number and closeness of access points along the highway. The internal street system shall be an integral feature of the overall design of a PBD. It shall be designed for the efficient and safe flow of vehicles without creating a disruptive element to the development.