Abstract:
Freight transportation planning and modeling in general, and Freight Trip Generation (FTG) in particular, is an area that is not covered as widely as passenger transportation. FTG mechanisms are different from passenger trip generation mecha- nisms, and they are driven by logistical decisions of establishments. So, the main goal of this research was to improve the understanding of FTG mechanisms and modeling in urban areas. The data for the study was obtained from Kocaeli Logistics Master Plan. Kocaeli is one of the largest industrial cities in Turkey with a population of 1,676,202 as of 2013 and has approximately 2200 industrial establishments. A preliminary factor analysis showed that FTG of TIRs is different from trucks and vans; with the latter two types are similar to each other. It was followed by segmentation of the similar logistical site types according to their FTG characteristics for each vehicle set using Analysis of Covariance (ANCOVA) and its associated post hoc tests. Then, regression models were built for the whole segment (called the pooled model) and for each logisti- cal site included in the segment separately, and statistical tests were performed to test the null hypothesis that the segmentation does not improve the t, thus the pooled model is sufficient. This procedure was named \market segmentation analysis". These analyses showed that the pooled model was sufficient for almost all the segments except one segment of truck and van trips. Following this, the segments with most zero-trip generators were modeled using a new approach which is called \conditional model" and compared with simple regression models of the segments. The results indicated that rstly, it was possible to group the similar logistical site types in terms of FTG patterns. Secondly, for TIR trips, the proposed \conditional model" showed an im- provement over the common regression modeling approach; with reductions in RMSE and MAE of 29.58% and 23.57%, respectively. Finally, some recommendations were made for future research in this area.
