ABSTRACT
This chapter explores several of the various types of models relevant to transportation planning. It deals with the calibration and use of models, since these two aspects are so closely related. The chapter focuses on models of transportation system characteristics and their interrelationships. The major inputs to all phases of stage V come from data collection, stage IV of the transportation planning process. The former category contains those characteristics commonly associated with the strength and motion of a transportation system, while those in the latter category are more akin to the physical development of a system and its use. A final illustration concerning the definition and measurement of speed regards the situation in which neither the distance nor time intervals are fixed for measurement. Primary constraints on top speed for any passenger carrying vehicle are its acceleration and deceleration characteristics. The speeds of various transit operations depend on several factors.
