Forecast of Truckload Freight of Class I Motor Carriers of Property in the Southwestern Region to 1990

Truckload revenue freight of Class I common and contract motor carriers of property operating in intercity service in the Southwestern Region has been forecast to 1990 using multiple regression analysis. Data were gathered on the dependent variable (truckload freight) and on thirty independent variables (economic indicators of the Southwestern Region) for the base period 1957 to 1971. Missing values from the time series data were estimated by curve fitting techniques to the known data points. Multiple regression analyses were used to measure the linear relationship between the dependent variable and a set of independent variables, taking into consideration the interrelationships among the independent variables. From these analyses, predictor regression equations were formulated using either uniform or mixed inclusion levels for all independent variables. Three equations were chosen for further analysis. The independent variables in the selected equations were forecast by extrapolation from the curve which best fit the known data points of each variable. Comparison of the three predictor regression equations, a Department of Transportation projection, and the closest fitting extrapolation of the truckload freight data, along with all the statistical evidence available, led to the selection of a "best" forecast,which is a set of four economic indicators.