Chapter 3: Local Road Planning 87 class and speed for the vehicles as they pass the imaginary loop. Types of Data Needed • Volume • Speed • Classification • Headway. Used for special calculations by traffic engineers • Gap. Used for special calculations by traffic engineers • Weigh in Motion (special loop configuration necessary) Data Applications • Benefit Cost Analysis • Design of Pavements • Geometric designs of intersections and curves • Phasing of traffic signals • Traffic management particularly in local areas • More efficient use of resources • Modeling of changes to the network. For example, construction of a new road and the impact on the existing roads The main advantage of the methods of automatic recorders or counting machine is that they can work throughout the day and night for the desired period, recording total hourly volume of traffic. Note: The DPWH has its own classification system that has 12- axle base classes. This can also be adopted by the Local Government Units so that they can also utilized the seasonal factors being generated from the DPWH long duration traffic survey sites to come up with an AADT.