Another view of transport system analysis

The components and interworkings of transport systems are outlined and described and some directions for improving our analysis capabilities are indicated. Particular emphasis is placed on the subject of demand analysis and on viewing the demand for travel as a dependent relationship between quantity of travel and the quality and price of travel rather than as a fixed "point estimate" or "requirement." Some explicit demand models are offered for improving our travel forecasting processes, and their relationships to price and performance functions are described both qualitatively and quantitatively; in so doing, the important characteristics of and ways for representing the time-dependent performance conditions of transport facilities are explained. Buttressing the discussion of forecasting techniques-of demand, price, and performance functions and their character, development, and interrelationships-is a section noting the importance of describing the differential as well as aggregate effects of alternative designs or policies, all as part of the system analysis.