The subject of this work is a description of basic terms and phrases used by the scientific discipline 'Traffic flow theory' as well as the history of the theory's development. Likewise, the work also encompasses basic indicators of vehicle movement, which are of aid in the description of vehicle movement along a motorway, as well as inter-vehicular relations in traffic. In addition to naming the indicators, the work defines basic relations between the indicators themselves. The work's main focus is two indicators of great significance; headway and gap. The latter's effect on traffic flow density is measured through methods of gap direction within actual traffic scenarios. Through analysis of traffic flow direction applicability, the work derives options capable of traffic direction on Croatian motorways. The analysis encompasses options provided by the law, examples of use of said legal options and eventual beneficial ramifications said options may bring to the collective traffic system.