Chapter 3: Local Road Planning 88 class and speed for the vehicles as they pass the imaginary loop. Types of Data Needed • Volume • Speed • Classiifcation • Headway. Used for special calculations by traiffc engineers • Gap. Used for special calculations by traiffc engineers • Weigh in Motion (special loop conifguration necessary) Data Applications • Beneift Cost Analysis • Design of Pavements • Geometric designs of intersections and curves • Phasing of traiffc signals • Traiffc management particularly in local areas • More eiffcient 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 traiffc. Note: The DPWH has its own classiifcation 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 traiffc survey sites to come up with an AADT.