The course notes include eleven exemplary applications which allow the students of Traffic Flow unit of the 7th semester in the School of Civil Engineering of NTUA to better understand traffic flow theory. The applications refer to the definition of traffic volume, speed and traffic density by presenting the relationship between the traffic parameters. They also include calculations for vehicle arrivals using statistical distributions and the estimation of the traffic volume and average route speed using the moving observer method. Finally they include a series of applications for the identification of the level of service and other parameters used in the traffic flow calculations for all interurban road types (freeways, with and without median roads with one, two and more traffic lanes per direction), following the new Highway Capacity Manual of the USA.