Transferability and updating of disaggregate travel demand models
Inappropriate decisionmaking due to these types of errors can account for premature investments in infrastructure in the case of overprediction and loss of labor hours, pollution, and low levels of service in the case of underprediction.TGMs are usually estimated based on periodic surveys of the travel habits of individuals or households.The average number of daily trips per person was higher in the Haifa metropolitan area (2.14 in 1984, and 2.03 in 1996/97) than in the Tel Aviv metropolitan area (1.83 in 1984, and 1.91 in 1996/97).The difference in the average trip rates may be explained based on the variation in land uses.Results of the study show that the estimated regression and Tobit disaggregate person-level TGMs are statistically different in space and in time.In spite of the transferred forecasts, the aggregate forecasts were also similar.The flow diagram in Figure 1 calls for the use of a prediction procedure which obtains the desired aggregate predictions based on predicted input data and the estimated disaggregate model.
The planners can perform forecasts for the same areas and, if justifiable, transfer the models to other areas.
The lack of mixed land uses in Haifa may encourage the generation of more trips.
Furthermore, Haifa's hilly topography may encourage more vehicular trips than in Tel Aviv, where shorter trips are probably done on foot.
Tel Aviv lies on level topography, with a well connected road network.
The metropolitan areas also differ structurally: Tel Aviv is interconnected like a spider web, including several minor cores with high-density population and employment concentrations.This paper is concerned with the application of disaggregate models to obtain predictions of aggregate travel flows required for transportation systems analysis and planning.